Yorick is a really balanced champion, that if you play right can have a deadly impact on the game. Things to remember is that early game you are extremely squishy. Focus on farming, rush a tear ASAP, and just poke down with your ghouls. The insane amount of regen your e gives you will mean you will our trade and sustain your opponent easy, assuming you have enough mana. Be Careful with ganks because you really have no escape. Just hit them with a slow, get the movement speef proc from your q if they are close and e for the regen.

Once you have your manamune focus on gaining stacks with your aa. Try not to push lane with your ghouls. The longer you are in laning phase the faster you will get your Muramana. If the lane is pushed, get golems and b (you'll probably be out of mana).

Be careful when you are oom, push the wave and b if you can, you are pretty useless. The longer you stay away from base the more oom you will get, no matter what point in the game it is, so don't forget to B!

Your passive reduced aa damage per ghoul you have. So if you are in a brawl spawn your ult for bonus damage to the enemy and for the 4th ghoul damage reduction.

If your ghoul attacks a champion under tower YOU WILL GET AGGROED, so be careful as your ghouls will attack the nearest champion!!

Use your W ghoul to block skill shots.

Ult when fighting for the damage reduction and the bonus damage for your clone.

Ult before you die to respawn yourself/ an ally.

Your ult does a % of your AD as aa damage. So ult the ADC for a 6th man during team fights!

If you know one of your carry's will get bursted (by for ex a veigar ult) ult them! They will have 10 more seconds to win the team fight after the team burned their ults to kill them!