This is a guide made be a player who only played Gangplank for his first 100 games of league of legends until I realized how underpowered he was compared to the other champions in the game. As time goes on riot tends to nerf the champs that are overpowered in the current meta and making champions like this look more viable. I have faith in the belief that Gang Plank could come back to the meta so I am here to help.

PROS
Good gold income
Self Cleanse
Global Map pressure
Awesome sustain
Ranged Harass in lane
The q can crit
CONS
Doesn't out trade early
No gap closer or escape
No hard cc
Requires patience
Uses mana

Ok so this is the deal with GangPlank. He does not trade well vs ad bruisers or tanks so what we want to do is out sustain them and keep up in farm. We start of with 2 life steal quints crystalline flask and we will have the E to cleanse any cc that would lead to a death and heal which might be the only real advantage he has over other top laners. The Q will give you more and more gold when you last hit minions with it so all you really have to do is survive with all of these survival tools and not feed. It is better to wait for a good timed gank or just try to assist a kill with your ultimate somewhere on the map to have a presence in the game over the other top laners. If you do get ahead of them in health from harassing while playing safe it might be possible to kill them alone but make sure you already have a solid health bar before committing to an all in. Make sure you ward when you can and not push the lane so you don't give up any kills.

With the core items in this build you can spilt push very fast and when someone responds to you. You have the option of using the Ghost Blade's active to run away. Also you can use his ult to clear save people that are being chased anywhere on the map. A lot of the items you have give you movement speed so catching you will be hard. Also a late game Gang plank is one of the scariest champs in the game with a high amount of critical chance. It will be very hard to for any champ to stop him alone with out getting 3 shotted by this build. Recognize who you can 1v1 1v2 or whatever and who you should run from. Also make sure you are using the hydra active to push lanes even faster and move around a lot to get maximum gold in a fast manner. The impact you will make on the game will be immense almost as if you were a baby version of shen but you deal way more damage.