Start with boots and 3 pots. Then start to build Manamune. After that buy Phage and the Giants belt. After Giants belt buy Trinity force from Phage and Warmogs armor from Giants belt. Then go for Atmas impaler that will give you attack damage from your health. And last item go Banshees veil that will make you even more tanky.

What are you maxing depends on what champion you are playing against. But usually it is the best to first max E that will give you sustain and will do a lot of damage. After that you should max Q that gaves you bigger damage and some movement speed. And at last you max your W that slows enemy down. As usually u upgrade ult at 6, 11, 16.

Yorick is GOOD against :
-Darius
-Teemo
-Jayce
-Shen
-Rumble

And BAD against :
-Cho'gath
-Xin zhao
-Trundle
-Nunu
-Nidalee