Hey this LMAO´s user-friendly guide for Yorick, the Gravedigger.
I got two reasons why I wrote this guide:

1) Yorick is underrated
2) Yorick is insanely OP with this build

This makes him ideal champion for ranked games!

I recommend playing him SOLO LANE - early harras, has "lifesteal", homing abilities, easy to last hit..what else u want?

Hes easy to master, pwns from early till late game, his ulti is just...just check this out Omen of Death and think about it a while.

Okay lets check this out :)

Ignite - finishing off, early game boost for ghosts, good for first blood

Exhaust - shutting down a champ, good for first blood

Ive found these two the most useful for Yorick. First blood before lvl 6 guaranteed (if ur opponent doesnt have flash or ghost)
-> lane dominance.

U may think these r good:

Flash - escape mechanism, flash to hit with Omen of War for moar chase

Ghost - escape mechanism, ghost to hit with Omen of War and even moar dps chase

Escape/Chase mechanisms r always handy, but if u got warded map and keep an eye on it, then its nearly impossible to gank u.
Yorick is already good chaser with Omen of Pestilence´s aoe slow and Omen of War´s speed buff.
Exhaust can be used also defensively and reduces enemys armor and MR.

Attack Combo: W -> E -> Q (-> R) and repeat..extremely good chasing

Omen of War - speed buff, resets auto attack, massive dmg with Sheen (later Trinity Force)...take at lvl 3 and max second

Omen of Pestilence - doesnt need a target to cast, aoe dmg + slow, brush checking, triggering spell-block abilities...take at lvl 1 and max last

Omen of Famine - "lifesteal", OP "lifesteal" with Spirit Visage, nice dmg...take at lvl 2 and max first

Omen of Death - 10s controllable UBERminion, 10s revenge time for ur ally, /win for u in teamfights (ppl tend to not focus the ghost..even if they shut down ur carry and it dies at start of a teamfight, u can cast this and all they did with that massive cc and summoner spells is lowering its dmg output by 55/40/25%), tower pushing, early dragon soloing
Who needs Undying Rage, Unbreakable Will, Intervention, Diplomatic Immunity, Chronoshift when u got mofoing Omen of Death!!!

Early game try to last hit with ur mouse skill, later (with Tear of the Goddess) use Omen of War and Omen of Pestilence "only"(lol I can spam em nonstop!) cause of lower mana cost.

With Ionian Boots of Lucidity, Spirit Visage and masteries u r goin to have 37% cdr. Yay for ghost spam.

Start with Meki Pendant and 2 Health Potion

U should b when u got enough gold for Tear of the Goddess and Boots + more health pots or ward.

Build Tear of the Goddess into Manamune and upgrade to Ionian Boots of Lucidity.

Start building Spirit Visage, taking Kindlegem first.

When spirit visage is completed, build Sheen.

Start building Trinity Force with Phage after Sheen.

THIS IS YOUR CORE:

Now u gotta decide if u wanna go tanky or want more dmg.

Tanky build:

Add Thornmail and Guardian Angel

Dmg build:

Add Atma's Impaler and Banshee's Veil

U r goin to be the most fed one, so dont forget to buy wards and/or oracle.

9x Greater Mark of Attack Damage - Bonus dmg to Q and E, ghosts AD and auto attack

9x Greater Seal of Armor - Provides u early armor.

9x Greater Glyph of Magic Resist - Provides u early MR.

9x Greater Quintessence of Attack Damage - Bonus dmg to Q and E, ghosts AD and auto attack

This rune setup is optimized for early game dominance.

Well, this is just beta version..my goal is to make easy-to-understand guide so more ppl gonna play this underrated OP.