Muktol

Goblin Rabblemaster isn't a legal commander (you normally place your commander in the sideboard), I would guess that you wanted to use Krenko, Mob Boss as chief.

Some suggestions based on my own monoR goblin commander deck (http://www.mtgvault.com/muktol/decks/edh-krenko-mob-boss/)
I would lower the number of creatures a little bit and add some artifacts/ support spells. Cards that protect your commander (artifacts with hexproof/ shroud) are always a good idea because Krenko has "I WIN" painted in red capital letters painted all over him, which makes him the perfect target for removal spells. If you want to add some further support look for artifacts that help to untap Krenko and thus use his ability again (and again, and again and so on). There are also some very good spells/ artifacts that help you with mass-pump (+1/+1; +2/+2; +X/+X for all your creatures)
Last I would look for some carddraw spells because with lots of cheap goblins you will run out of handcards pretty fast.

Greetings
Muktol

*like*

There are some cards that work really good in sacrificing decks like this one: Grave Pact, Altar's Reap, Tragic Slip, Bone Splinters, Cauldron Haze, (Sylvok Lifestaff)
If you don't need her for removal then I would switch from "Olivia Voldaren" to "Stromkirk Captain" (at least sideboard it). The Captain will increase the chance of survival of all your creatures significantly.

Greetings
Muktol

I would sideboard/ remove "Eland Umbra" and add 2 additional "Silhana Ledgewalker" instead. You could also lower the number of lands by 2-4 and use "Abundant Growth".

Greetings
Muktol

I did a similar deck some time ago: http://www.mtgvault.com/muktol/decks/wb-tribal-vampire-sacrifice/
I used some other creatures to sac but perhaps it will help you with some ideas.

Greetings
Muktol

I would change from "Erdwal Ripper" to "Stromkirk Captain".
Furthermore I would increase the number of "Bile Blight" to 4 but sideboard it. If you want a -X/-X spell take a look at "Dismember" or "Tragic Slip". If not a simple 'destroy creature' spell like "Go for the Throat" or "Terminate" will do the trick.
If you like to work with removals and/ or sacrificing effects then "Blade of the Bloodchief" could be very interesting for you.

Greetings
Muktol

I mean no offence but you might want to read http://www.mtgvault.com/muktol/decks/how-to-build-a-deck/

I know that the first decks are often built with the cards available at home and that this pool is limited. Such information is best placed in the deck descriptions right with the description and the tactics.
If you need help on a built, and on which points, should also be put into the deck description and perhaps the deck tags.

Greetings
Muktol

If you really want to win by beatdown, and not via commander damage then I would remove many of the equipments that only affect a single creature (swords and so on). Thos should/ could be replaced with mass-pump artifacts/ spells: "Dragon Throne of Tarkir", "Konda's Banner" and so on.
Basically I would also try to reduce the number of creatures a little bit because 48 is awfully much. "Stoneforge Mystic" and "Stonehewer Giant" would be a good start if you don't need to rely on a certain piece of equipment. "Ranger of Eos" depending on the average mana-costs of your creatures. "Jor Kadeen, the Prevailer" sounds nice, but if you start to reduce the number of equipment/ artifacts it will get difficult to activate his ability.

If you're looking for cards to add I would take a look at the two diamonds (http://www.mtgvault.com/cards/search/?q=diamond&searchtype=name&mco=%3d&mc=2&t=Artifact&ps=20 (the links seem to be down)) fitting your color. A reduction in manacosts is always a nice thing.
Also creatures with battalion, like "Frontline Medic" or "Legion Loyalist", could be an interesting option .

One last thing: If you're not playing competitive but against friends with this deck, keep your fingers away from mind control spells like "Zealous Conscripts".

And so on. Sorry I'm a little smashed up and tired at the moment so my help will be limited.

Greetings
Muktol

In my opinion there are two ways of optimizing this deck: Adapting it to a have good chances against all decks (which means a proper sideboard) or making it efficient against your friends decks. From my experience it's better to go for the first option because if you have a deck that wins 10 out of 10 games it will become boring for your friends rather fast and they might stop playing with you (or against that actual deck)

Flyers are normally rather slow and weak but hard to remove with only creatures...they are the typical pain in the ass you can't ret rid off easily. So there are 3 ways of dealing with them: Block/ kill them with creatures, destroy them with spells or be faster than your opponent. From my experience it's always better to put some pressure on your opponent and force him to react to your plans than just to sit there and react to his.

As for "Spidersilk Armor", you might want to take a look at "Spider Umbra". It's no global buff for your creatures but it gives +1/+1 instead of +0/+1 and it provides the enchanted creature with 'Totem Armor'

Just for information: When playing "Fling" it won't trigger e.g. "Nivix Cyclops"'s ability because you have to sacrifice the creature before you actually get to play the spell.

Like the top poster I'm no big fan of a modern deck that is pushed into legacy-legality by only one card. As you are working with many enchantments I would change from "Spidersilk Armor" to e.g. "Ethereal Armor"

Also you want this deck to be an aggressive deck thus cards like "Fog"/ "Holy Day" (If you want to use a fog effect go for "Moonmist") should be put into the sideboard. The same is true for cards that have rather high mana-costs or are used in longer games, like "Privileged Position".
The free slots could then be used for some pump/ protect spells like "Ranger's Guile" or "Vines of Vastwood". If you really want some protection use color protection spells like "Apostle's Blessing" or "Emerge Unscathed". Those spells enable you to withstand burn and targeted descruction spells and (if played on your turn) make the creature unblockable for all your opponents creatures with the chosen color.

Another interesting option could be "Mayor of Avabruck". In his human form he's pretty unspectacular. But when flipped he provides all your wolves with a +1/+1 buff and produces a 2/2 wolf token every turn.

You should also rework the manabase a little bit. At the moment you're using 47 green /27 white mana smybols. I would reduce the number of plains a little bit and use more forests. Also you should add some more duallands because double mana-costs can be a little bit tricky to pay with just basic lands.

Greetings
Muktol

My own pauper izzet deck (http://www.mtgvault.com/muktol/decks/ur-pauper-izzet/ seems like the links are down at the moment)uses less control spells and more buff spells.

Some suggestions, based on the deck mentioned above:
Titan's Strength, Assault Strobe, Distortion Strike, Rift Bolt, Mizzium Skin

I would add some more dualllands (or searchlands) to make sure you have the right mana when you need it.

Greetings
Muktol

I would try a split between "Weapon Surge" and "Bloodmark Mentor" (or "Legion Loyalist" if you want a more aggressive but cheaper version). Some testgames should show rather quickly what works and what doesn't.

*like*
I would use, at least in the sideboard, "Bloodmark Mentor". This would increase the chance of survival of your tokens.

I would rely less on creatures and some more on spells, especially if you want to use "Guttersnipe"...he needs a lot of instant/ sorcerys. If you want to work with some creatures try those who benefit from having other spells played or deal damage to ALL opponents: "Young Pyromancer" (Which can be rather interesting with e.g. "Impact Tremors"), "Monastery Swiftspear" (Prowess), "Fanatic of Mogis" (Devotion), "Kiln Fiend", "Charmbreaker Devils"

If you want to use more/ other spells I would focus on those with flashback, rebound and such mechanisms: "Devil's Play", "Firebolt", "Increasing Vengeance", "Past in Flames", "Recoup", "Staggershock".

"Sizzle" deals damage to all players with a good mana/damage ratio, and a simple "Fireball" could be an interesting finisher
"Manabarbs" hurts all players (also you) but as you are playing burn and using mass-damage spells this could help to finish your opponents very fast.
"Isochron Scepter" can be very good, but you have to focus on (cc1/)cc2 spells to use it effectively.

A basic tip for deckbuilding: Try to minimize the number of different cards and maximize the number of the remaining ones. This increases the chance of drawing a card you really need.

Greetings
Muktol

I hate to say it but "Breaking // Entering" isn't supported by your commander's color identity.

If you need a huge amount of mana in different colors then you can do it in some different ways. Ramp/ landsearch, dual/tripplelands or sources that produce mana of any color you need.
One of my favorite tactics here would be defender ramp. Use "Axebane Guardian" and some additional defenders to get mana while your opponents tries to get around your blockers. Add some protection to prevent your defenders from beeing shot away and many decks will have a hard time getting through your walls. I have used this in my <a href="http://www.mtgvault.com/muktol/decks/gw-tribal-angel/">G/W angeld eck</a> and it works like a charm and angels are anything but cheap to play.

The drawback on "Progenitus" is that you can't enchant him, equip him or anything. So if your opponent manages to get rid of him (mass removal or forcing you to sacrifice it) then its 'game over' most f the time. Nearly any deck that focuses on one big finisher has a backup plan, so I would also think about that.

If you want to get some help and advice a good thing to start with is a deck description: What is the strategy of the deck, is there any budget limit, was this deck built for any special format (commander, tiny leaders, singleton), the card legality and so on.

I mean no offense but you might want to read <a href="http://www.mtgvault.com/muktol/decks/how-to-build-a-deck/">how to built a deck</a>. This gives a rough guidance on strategy, card choices, number of cards and so on.

Greetings
Muktol

Thanks. I removed 2 "Harmonize" and added 2 "Peer Through Depths". Some testgames will show which card I like better.
I also found "Tolaria West" while building a commander deck and this enables me to search for cards with {0} costs, so 2 of them also got added instead of 2 island.

I would use 4 "Gods Willing" in the mainboard and have 2-3 "Apostle's Blessing" and/ or "Brave the Elements" in the sideboard.
Or you could do a 2/2 split between "Gods Willing" and "Brave the Elements" in the mainboard, have 1 additional copy of them in the sideboard and have 2-3 "Apostle's Blessing" in the sideboard. This would maximize your versatility, give you a good idea of what works and what doesn't and the chance of changing something from game to game.

Depends on the situation. "Brave the Elements" protects all your creatures from damage while "Gods Willing" protects only one creature but allows you to scry....for this deck I would prefer "Gods Willing" as of the scry effect. If you're having troubles with artifacts you could also choose "Apostle's Blessing"