Your priority is Opponent player and not the creature, but when he spell for example, ,,Lanowar Elves,, not bad to destroy him. He gives +1 mana for tapped and it can make problems. A really big problem can you make a card as ,,Leyline of Sancity,, are you in the game ended :D
Try to use more creature spells you give for one like, Lava Dart,, or, Grapeshot,, (you can clone and destroy monsters and more) -, LB, to a player,, Grapeshot, within two monsters or the one in the case of two lives. On the destruction of creature is mainly added card ,, Volcanic Fallout,, (2dmg to all)
Try not to hold cards in hand, but playing them as soon as possible, the risk that oponnent player will have discart and do not have much opportunity how to draw hand back as +1 card per round it goes wrong. Not too bad to add to the package, Browbeat, from sideboard. Also do not take much account of their lives if they did not approach zero, anyway do not do anything with it, because you have almost no chance of defense.
It is best to get oponnent player 10 lives and then play,, Hidetsugu's Second Rite,, and you win. It's a lot of ways to do it. In 7,5 / 10 games you win 4-6 round.
For examp.: 1 Turn: Land; Vexing Devil
2 Turn: Land; Lava spike; LB
3 Turn: Land
4 Turn: Land; Hidetsugu's Second Rite