You need a way of securing mana gain. Right now you're gambling. A way that would work is putting in only forests and relying on the Slivers to generate other kinds of mana, since you can search for and play Gemhide quickly. Of course, you would also need to figure out a way of protecting gemhide, otherwise he's going to be absolutely fucked once the opponent realizes he's the crux of your deck.
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Thing is I have draw advantage cards in there to counteract the fact that the deck is 77 cards. I know of some cards that are better than the ones I have, like Jace Mind Sculptor instead of Beleren, or Glimpse the Unthinkable instead of Tome Scour, but the prices for them are ridiculously high. Cheapest Glimpsex4 I can find are going for 36 dollars right now on ebay, which is more than I can afford in my destitute student life. :P