Kog'Maw is simply one of the best AD's in the game. He is so strong at any stage of the game... Unlike Tristana who is strong early and strong super-late game, and MF/Cait who is primarily strong early, without the limitations of range like Corki/Vayne... Kog'Maw is just a perfect blend of early-game dominance and late-game scaling.

Kog'maw can be played AP or AD so a combo can be OP if you just build the right items.

I build a Hextech gunblade for the AD,AP and the life stealing gives you a little help in the begining.The nashors is for attack speed that necessary for kog + it also gives a bit AP and cd redution that can be useful.The guinsoo's is a rly good item on kog seeing how it gives AD and AP and also attackspeed on use.Then too finish take a rabadons just too boost you're Ap and a Infinty edge for AD and a bit crit chance...

With this build you should go bot with a good support and try to last hit as many creeps as you can this build is not cheap so try to get as much kills turrets,and creeps.

You still need to play defensive seeing how you're very squisy with this build and don't chase people.

If you don't want to be so squisy than consider leaving the Infinity for a Frozen Mallet or a Gaurdian Angel

If you are having trouble in the early laning phase with the other team (, it's often worthwhile to grab a fortitude potion. That way you can engage in a fight, use the potion as a "heal" part way through, and hit even harder with your physical attacks. It can be a great way to get momentum back if things aren't going your way.

Early game, try to line up shots with your E while the enemy champion is close and tangled up in his mobs. Once he's slowed let loose with W and get 3-4 hits in before he can get out of range. If he's real close don't forget to Q!

Check bushes when you haven't used R recently enough to have the mana cost penalty. Remember that the revealed area is pretty small, so it won't check a whole bush for you.

Try to position yourself in fights so that you have obstacles between you and the enemy, Kog'Maw excels at jungle fights because he can keep hitting with his awesome attack range and his R. Try to line up your E so it will both damage champions and block off escape routs

While it is, of course, important to shut down enemy caries ASAP, you do very good damage to tanks as well.

Be aware that using R can reveal your location

Drop your R on squishies or groups during fights, it's up every 1.5 seconds so if you've got the mana you need to make sure to keep this going throughout engagement.

Beg for golem, it lets you spam your R like crazy (the ability is on a very short cool-down)!