Yorick is a champ that summons ghouls to attack His enemies. He has one of the best Harasses in the game, and a fairly good sustain, but is pretty mana hungry. Laning shouldn't be difficult, all you have to do is summon as ghoul whenever the your opponent wants to farm, and you should win with an easy cs lead. Just don't over extend because Yorick doesn't have a great escape. If you plan to use your skills for farming use Q and W because their mana costs are lower than E. You can start to extend a bit more if you hit 6 because your ult should allows you to 2v1 extremely well. If you have a very fed adc, you should ult them.You can also use your ult to take down turrets because this procs your passive, and will take turret shots for you.

Ignite-
When dueling in early levels the opponent will probably flash out when he realizes how much damage you do. Ignite is a great way to finish them and snowball your lane.

Teleport-
You won't use this most of the time unless your team wants early objectives

Pros-
Can rip a hole in almost anyone's ***
Good sustain
amazing harass
can block skill shots with W
a bit of cc
Yorick walks into a bar, there's no counter (almost)
Cons-
no real escape
not very fast