Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
There is my build for Gangplank. I chose to max his Parrrley because I think it's his most powerful add useful skill.
Sheen : you need it. 100% more dmg on your next physical attack (parrrley is physical). When you use parrrley, sheen is activated and when the bullet reaches the target sheen get used. In addition, sheen will provide you enough mana to do well.
Trinity Force : it is an upgrade of what Sheen does, and it gives you slowing attack with more health.
Last whisper : 40% armor pen. I don't think I'll need to explain.
Ninja tabi : or mercury tread depending on the situation. your choice but don't take berserker greaves they are useless, last whisper already gives you attack speed.
Infinity edge : Of course
Avarice blades : for crit(24% for two) and money. Buy them early in the game.
Phantom Dancers: for crit, movement, and attack speed.
Executioners Blade for the lifesteal and crit chance with the ability to prevent 50% of healing
Mandred's Bloodrazor: for attack speed, damage, and armor
If you have the money, sell avarice blades and get a Executioners Blade for the lifesteal and crit chance. And finally, if the game is very long, get the Phantom dancers. then you can trade in your boots for Mandred's Bloodrazor.
When the game start, buy crit brawler and 2 health potion and put youself into harassing mode. Try to lane with a melee so you'll be able to avoid damage and do hit and run.
Don't waste your mana when you know it's useless to harasse.
Focus DPS: you you can burst to 650 damage at level 8 if you do well so on a teemo with 1100 HP It's kind of funny.
Use cannon barrage to defend towers.
Your remove scurvy is not only a heal that can save your life by removing CC. It allow you to feint you oppenent.
For exemple, you have 300/1300 HP and Teemo want you. You are staying around your tower and defending. Your remove scurvy is lvl 5 and can heal you for around 400 HP but you decide to wait. Suddently, teemo flashes into your tower and tries to kill you, he blinds you and....HOOOO HEALING +400HP....BANG CRIT ON TEEMO. Teemo gets killed by tower and you survive with 200 hp !