Help please?

you might also consider faithless looting, in addition to scotts comments,  it can synergy well with varolz and help you get some consistency. It's fairly cheap and could replace cards like jarad's orders farseak and grisly salvage. Which are slow, and looting doesn't reveal everything to your opponent. Duress doesn't seem right.  Maybe sideboard the duress. If you have access to it, gravecrawler works pretty well with lotleth and varolz to sac for regen.

Not a bad start to this kind of deck though.

also, a piece of advice from personal experience.  When I first started playing rtr I tried very hard to make corpse jack work as a card and it usually didn't pan out. And I've tried a few times recently. I'd consider replacing him with dreg mangler, 3 haste damage is pretty good.