is a nice item on him. With grave hitting, its just a sense you get playing games with him. If you play enough Yorick, you'll eventually just become used to how much damage it does. If you want to get better quickly though, something you can do is Q a minion, see how much damage it deals, then only Q minions whenever they are below that health cap. You'll have to keep checking the damage, but it should help overall. Build-wise, lots of things are good on him, but I like this build:
or
depending on the CC. Triforce is good because of the synergy between it and Yorick's Q, DD gives some nice AD, LS, and its passive is nice for dueling. Deadmans for the armour and movement speed, Spirit Visage for the MR and heal increase. ZZ adds more pushing power to your build, but its something I'll pick up first, only if I'm getting thrashed in lane. Tabi are nice against a heavy AD team, and Mercs are good against a heavy CC team.