*************Dont be fooled by the numbers. if you think gangplank at the end of the game will have 200 atack damage well , he wont he will have 300+ even 400, his armor penetration is 31, the stacked items is not implemented.*********


Gangplank was my first hero, until now i lost much time getting better with him and finnally i got one build (which i use frequently) that made him tanky and kills a lot.

Since you "wont do damage" early game, armor penetration will get you 31 bonus+10% wich make you deal a lot of damage even with parley on lv1. Without items you can still kill easily.
The armor runes will let you stay on lane more, since you wont take much damage. The cooldown reduction per level its because you can change the tide of any battle between lv 17-18. giving you parley 2 sec cooldown and tons of damage in small time.

The crystal will allow you stay on lane a bit more farming, killing whatever you feel up to. The potions, of course, will offer you surviability on lane.
Now the manamune can be easily stacked and wil lgive you a nice boost of atack damage early game and a nice mana regen. Ninja-tabi will let you take damage for a longer time. Atma's will offer another atack boost with you can get to 300 earlier than the others.
Warmog's will let you "tanky", and will offer another boost of atack since you have atma's earlier.
Infinity will help you get kills more easy.
Trinity force will offer you everything you want: health(atma's), mana(manamune), atack speed+damage, slow and one nice sheen ability of 150% (parly+enemy champion=instant kill)

I think i did it wrong, but what you need to know is: depending on the other team, get your heal up first, if the team are running too much get your boots and get raise morale up first. If you think you aprley is killing and want more damage maximize it first.

Every match on league of legends depends on the other team.

Gangplank is one nice pirate farmer, donr underestimate parley bonus gold, it will give you advantage against 1x1 on lane if you are soloing, or advantage if there is a support there and you can farm more than the other. use parley as much as you can to farm, or to get kills.
Dont go spamming parley on minions or else you wont have mana to kill oyur enemy.

I take exhaust and teleport, exhaust will let you kill any enemy champion, and if they tower dive you dont be afraid of using it on him/her (always use on the one that is dealing more damage). Teleport always come in handy in any situation: helping you backdoor, defend a tower, get to a ward to save time....Anything

PROS
-Its cheap
-advantage on early games
-good on any phase of the gmae
-helps your team if there is no tank (or the tanker is not tanky)
-can change the tide of a teamfight

CONS
-Sometimes can not reach the goal
-getting kills is easy, being ksed is even more easy
-if you dont play smart you can get pwned