First thing, this is REALLY basic for gangplank. Whenever I play it ends up being situational later game, but if this is your first time playing I recommend doing this build because you get your 100% critical strike and lifesteal.

What you want to do is go mid, makes it a lot easier on yourself and you can gank your enemies with your team a lot easier.

When you start you'll have about 25% critical chance, which basically means every fourth shot is a crit/you have a 1/4 chance to crit on the next shot, same thing and it helps a ****ton.

You know that sion chasing you down? Oh you just got stunned? Remove Scurvy, and your problems are gone. Save that to your advantage.

You don't want all critical strike, because you want some armor penetration for harassing your lane and dealing more damage. I've seen gangplanks go mana regen runes or ability power runes, which I think its ******ed because they're just hipsters and want to make their own failure build. Gangplank can be played a variety of ways, but using crit chance (or damage) is going to help you in the long end.

Spells that are useful (in order):

Flash/Ignite: Good for a combo [(Ult + Flash + Parrrley + Ignite) this is in your 1v1 lane mid or if somebody is low in top/bottom that you want to kill] Almost always secures a kill, especially mid.

Smite: Jungling is really good for gangplank except it requires a little bit different runes/masteries obviously. A guide for this should come later.

Ghost: I thought about taking this to go with my E "Raise Morale", to make yourself quicker. In my opinion, ghost is used more so to get away than to secure a kill so it would be best to leave it be.

Exhaust: Considering you can speed yourself up and your melee attacks/parrrley slow your enemies slightly thanks to your passive, you won't use exhaust much unless you aren't good at catching kills.

Teleport: If no one on your team has this, I would suggest substituting ignite for this. Really handy in case of back doors, but make sure some one else can take this so you have both suggested spells.

Heal: You don't need this because your W is already a heal and it removes CC from you.

Clarity: Clarity for any champion becomes useless late game. If you really need mana, substitute a bloodthirster for a manamune (for damage AND mana)

Revive: Not useful because you can remove any CC effects and heal yourself.

Cleanse: No tank? No cleanse.
*Fortify fits between here* (Not a support/tank, no fortify)
Clairvoyance: No support? No clairvoyance.

I take 21-0-9, but you can shape it however much you want. Focusing on the crit chance/strike in the offence, and mana regen in the utility so you can still spam parrrley and remove scurvy when you need it.

Grog Soaked Blade

Description:Passive-Gangplank's basic attacks apply a poison debuff for 3 seconds that can stack up to 3 times. Each stack deals (3 + [1 x level]) magic damage per second and slows the target by 7%. This is a great passive. The slow is great for fighting champions and the poison is great for farming

Parrrley

Gangplank gains extra gold if Parrrley deals a killing blow. This ability can critically strike and applies on-hit effects, including his passive. Gangplank's bread and butter skill. I have maxed at 875 damage to an enemy champion and I am sure it has the potential to do much much more. It also has an extremely low cool down.

Remove Scurvy

Gangplank consumes a large quantity of citrus fruit which removes all crowd control effects on him and heals him. This is an extremely useful spell. It has great synergy with Raise Morale. Get out of a stun snare suppress etc. and speed away.

Raise Morale

(Passive): Gangplank's attack damage and movement speed are permanently increased. (Active): Gangplank fires into the air, disabling his passive boost but inspiring himself to gain additional attack damage and movement speed, with nearby allied champions receiving half that amount, for 7 seconds. Extremely useful in team fights and in getaways.

Cannon Barrage

Gangplank signals his ship to fire upon target area for 7 seconds. Each cannonball deals magic damage to all enemies hit. Enemies caught in the area of this ability are slowed by 25% for 1.25 seconds, with the duration refreshing if one stays in the area. A great spell to pick up some assists or kills. The whole map range makes it a threat to all enemies

The most BASIC, and I really mean BASIC items you need to gangplank. This build is designed to get you a kill, not designed for situations like heavy AD/AP on the opposing team or other situations.

(Not in order)

Phantom Dancer (Both are needed to reach that 100% crit chance)
Phantom Dancer
Ionian Boots of Lucidity (Helps on your cooldowns)
Infinity Edge (NEEDED for his Q/heavy crits)
Bloodthirster
Bloodthirster (2nd one can easily be substituted for frozen mallet and/or trinity force)

Pretty much this build WILL get you called a noob and people will say "only noobs play gangplank" All champions are cheap in their own way, yi/tryndamere/fiddlesticks/nunu/everyone.

EXTRA: If your team is REALLY dominating, check out buying a Rabadons Deathcap instead of a second bloodthirster, so your ultimate can do more damage and you heal more from Remove Scurvy.

Pros
-Crit chance relatively high since the start
-Good at 1v1
-Can get rid of any CC (unless multiple attacks are singled out on you)
-Fast
-Can dominate anybody in mid lane. (Only problem i've had with anybody was Kog'maw because of his range and he was pretty damn good)

Cons
-Squishy
-Does bad against people who have really far range (Damn you kog'maw.)

I was going to put this in the intro, but it really goes here.

When you're in a lane (assuming mid) don't use your parrrley on minions unless theres nobody in your lane and you are going back soon. It really can be a mana drainer.

Use parrrley on your opponent to keep him away and staying away. If you're lucky you may even get him to switch out with someone else (that's always funny to see, when you force Ashe to switch with malphite and still wreck him, true story)

Also when you back you can activate your ultimate when the minions/enemy champion(s) attack your tower. By the time the next wave is back, you'll be back at your turret.

Obviously don't run into a teamfight by yourself. Position your ultimate so that its surrounding the enemy team, which should be the initiatior (telling your team, hey go now!) and go do your business following your team.

If their team has an ashe/caitlyn/vayne/kog etc ranged carry hiding in the back, if you're cocky than flash to them and deal them out. If you're not a cocky one then work your way to them.

Thanks for reading and have fun dominating as one of the cheapest characters in league. Fun as well as cheap though.

If you made any suggestions for this build, go ahead and put them down, but keep in mind this is REALLY basic and the improvements will probably be covered later on. Yes, trinity force is good to have for the sheen effect, so if you'd rather have that, replace a BT (bloodthirster) with that.