Hello welcome to the guide for gangplank I hope you read the items section if anything at all it is the most important and a little craezy. I enjoy GP as a top and he is very good at sustain and damage output. He is a good character to learn if you want to play top. Thank you for checking out the guide!!!!

Boots of speed x3 health pots if jungler ganks are strong early.
Cloth armor x5 health pots if heavy ad bruiser top lane.
x2 Dorans blade for extra damage and health great item for gp.
Phage slow stacks with your posion slow good health boost also.
Atmas Impaler great armor and crit chance this items passive stacks with your health to get more ad with the x2 dorans and phage you will have nice ad.
Frozen Mallet great health like I said it stacks with atma passive along with increased slow.
Maw of Malmortius good ad bonus' and the passive is amazing vsing a enemy ap good defensive bonus' also.
Zekes Hearld good supporty item for the team this will increase your heal from your W and buff your attack speed stacked with your E plus the life steal from it. This item will also give out a offensive aura to your team good for team fights.
Frozen Heart great for shutting down ad carries lowers your cd's which is good for you to spam Q etc. also gives extra mana which is nice if you dont get blue.

I go Teleport and Flash teleport to get into team fights fast and flash to get away from ganks if your W isnt cutting it. I can see you going Ignite/Ghost to chase and finish off people with mad life steal or heals like Sion ult Morgana perhaps or other ad carries.

I go 9 21 0, I like focusing on the tank aspects of the trees it is good for extra armor if your top lane and health, cooldown reduction in this game is also good to spam that Q if you need to or if your in a pinch and without that CD reduction your W wont be in time to save you! The extra movement speed to get away from dem ganks is also good to if your above 70% health which should be EASY with dat W. You can also rock the 21 9 0 masteries focusing on damage but you really dont need it with the runes I have setup you do fine damage early game.

I went 9 armor pen for marks because your going to want to eat some of that armor your enemy has Top lane if they are laning correctly with the champion. Armor seals because you are top lane chances are the enemy will be an AD also these provide great armor early game makes you very tanky especially if you go cloth armor first also. Magic Resist Per Level glyphs AP carries are usually weak early game and get better late so no need for flat resist and plus you are not laning against an ap top usually but then again they are weaker early as I said. Then we got dos quints I am rocking some Attack Damage quints because I am going 9 21 0 into tanky and early game damage will be better with these. ( you can also go health quints for your early but they dont really matter late game )

I obliviously went into the Q more then anything else being the main damage dealer and slow then your W for remove from CC and nice heal. Lastly you go into your E which gives your movement speed attack speed etc good for chasing team fights not best thing for a tank though.

Thanks guys for reading this guide and I hope you enjoy it leave comments if you want thanks!!!!!!!