This is my first guide give it a try and Let me know what you think.

Marks - Armor Pen ( Early game farm/Harass )
Seals - Armor ( Sustain )
Glyphs - Magic Resist / Level ( Sustain )
Quintessence - Movement speed ( Harass )

I set up the Mastery Tree to play-off of both the AP and AD sides of Kog.

The main reason I set up the build the way I did is to get people to see that Hybrid Kog is a very viable Build if done correctly.

To start pick up Boots of Speed and 3 health pots

Next I will get Sorcerer Shoes ( this will help boost the damage of you W early game )

Then we begin to build the infamous Madred's Blood Razor ( the 4% Magic damage based on health
+ your W at 6% fully leveled = 10% magic Damage based on Health. Most tanks will not be expecting that kind of damage they will most likely build to counter your AD Carry. Even if the tank counters you pick a DPS to Target most players will get some sort of health based item to make them "less squishy" this makes them an easy Target just hit W and watch there health melt away.

And finally to finish out the Core build pick up a Frozen Mallet. Gives you great health and will enable you to lock down anyone trying to escape.

the rest of my build is subject to change. if you are owning get some more damage and attack speed. need more sustain grab some Armor/Magic Resist/ Health items.

As most Champs you want to get all 3 abilities in the 1st 3 levels then level your bread and butter ( your W ) and of course grab ult at 6 and finish leveling the W . the rest is up to you.

Ignite- For extra Damage.

Ghost - For harass and evasion.