Attention: In order to understand this guide, you should be able to do the following things:
speak English properly
have played at least 50-100 games so you know all items
read the spells of Gangplank before
make sure you understand the spells
make sure you understand what "applies on-hit-effects" means

I will not explain you everything in detail, this is a comprehensive guide for advanced players who want to have a quick introducktion for Gangplank.

Hi, I'm a silver (hopefully not for too long time any more) leauge player and this is my first guide on Mobafire. Actually, i have not been playing Gangplank for a long time, I just recently baught him and felt like there is no good, short guide (except the AP guide i completely agree with that one) on Mobafire that explains Gangplank's playstyle and contains a half-way good item constellation. I carried some games with my core build with the two Infinty Edges so i felt like i have to share it. Have fun reading it, it's not too long. :)
Note: The build is not finished, only provisional, there will be some changes in the design. (cause i wanna play and not just write guides all day long)

How to play him

Gangplank is a melee Carry champion based on constant harrass with his Parrrley. He is weak and squishy early game so you have to play safe on lane, don't expect that you will make many kills unless you jungler comes or your enemy sucks. Play safe, keep farming and if your enemy goes agressive, escape with Raise Morale and/or Heal Scurvy.
Gankplanks ultimate Cannon Barrage can be cast on the whole map, so watch out for lanes who need help or for counterjungling. It's also a great escape tool or an initiator for team fights.

Why shoud I play Gangplank?

Gangplank is a quite underestimated champ, because some people simply get the wrong stuff with thim. His has great damage mid to late game, a heal that sets him free from all cc (great against Amumu, Hecarim or Nasus) and his Raise Morale is one of the best spells you can get in a team fight for helping the tanks to initiate or giving the ADC bonus damage. I recommend to play Gangplank only for experienced players, because if you don't play carefully, your enemy in lane will exploit your early weakness.

Basic playstyle with this item build

This build contains Iceborn Gauntlet, so it's important that you kite enemies before you enter a fight. With those items, you are not that tanky as with most guides you find, but your heal is stronger and you got low cooldowns you you can spam your q and keep enemies away with it. this build should help you out if your team is behind in towers, farms or kills. Now you may wonder why I get Iceborn Gauntlet so late? Simple: You got a passive to kite anyways, it just works much better with Iceborn. Anyways, you will have high ad and high crit chance, so you will deal enormous damage.

Pros:
Strong mid to late game
Utility for the whole team
Global Ultimate
Hard to gank
Strong heal
Slight cc with his Passive Grog Soaked Blade
Arrr, he's a Pirate
He says cool stuff

Cons:
Weak early game
Hard lane against tanks, rangeds or champs with high burst
He has scurvy

As I already said, this is a comprehensive guide. I just wanted to give you some help with items, skill sequence and give you some pros and cons. Please give me feedback, feel free to discuss about the guide. I will make a change log too as soon as i change something.
I hope you like the guide, though my English is not the best and i wrote this spontaniously. If you like this guide, I'll probably do a Renekton guide too.
See ya in league :)