This is a tricky little deck with a complex set of mechanics at play.  Most creatures confer a benefit when they hit the field.  As a result, you want to play them frequently, by bouncing them with your Cavern Harpies, Erratic Portal, and Silver Drake.  Additionally, most are color-dependent, so use your Visionaries to make sure your opponent's creatures are the correct color to be bounced or destroyed.  Use the visionaries with Tsabo's Assassin to keep your enemy's field clear, or with Necra Sanctuary to keep a steady stream of damage going.  Alter Reality is great with Crimson Acolyte, Sphere of Truth, Deathgrip, and the Familiars.  Cavern Harpy makes a fantastic blocker: for 1 life bounce him back to your hand and she's ready to do your dirty work again.  Top-decking is your friend and your opponent's enemy.