Hello everybody! This is my first guide and i really hope that you like it. I've been maining Gangplank for a great deal of time now and i'd like to share my success with you <3. While using CritPlank is extremely entertaining, it also takes a while to master so bear with me here. Below you will find other helpful tips to being a successful Gangplank. (though most people just come to see the build Q_Q)

Though Jungling as CritPlank isn't a very ideal strategy, it may be viable in ssome cases:

When you have Red buff ~
Having red buff (preferably the enemy's) makes ganking much easier, ganking bot for example becomes a matter of getting your teammate to get close enough for you to E, then Use your Q to slow him (cuz u haz da red) and wail on the opposing teammember.
Counter-Jungling ~
This may need a sort of tweak in the above build (which i'll probably make), but it's still possible! Just take flash+Smite and have 1-2 teammates follow you into the enemy blue buff camp. Make sure to take the jungler out FIRST, to severely handicap him for the remainder of the buff duration. You also may need to rush Wriggle's to continuously ward the enemy buffs.

PROS
Can melt away HP in no time at all
fun as hell
can carry extremely well
great sustain
CONS
Can be shut down with bad early game
A bit squishy early game
Doesn't snowball well
takes great deal of practice

Though not as important as with Irelia, farming with Gangplank is pretty essential. If laning with a partner, have him/her allow you to farm up until you get Wriggle's, after that farming is a bit less essential.

This item is very helpful because of the sustain it gives early game. Also, when jungling/counter jungling the active is extremely helpful

This item gives a very versatile gameplay style, but what we're focusing on is the Mana, AD, and Crit chance. The AD is very helpful for the sole purpose of increasing you're soon-to-be incredible damage. The Mana is so you can eat moar oranges :3. The Crit chance is for...well that's self explanatory.

The large AD boost this gives you will really speed up you're late game and have you getting kills in no time! The passive will really start to come in handy after you purchase you're first .

This item will give you a good jolt of movement speed, attack speed, and Crit chance. With the preferred runes i gave you above, you should have 100% crit by now. C'mon, running faster than everyone else, melting health away, AND a Q that can crit? That's what i call a carry critplank.

Though you can't stay in the back of fights like most carrys and ranged champions, getting up close and shooting them in the face is just as viable. You want to make sure to focus the squishiest, which is generally the AP carry. You can generally go for the support as long as she's helping out the remaining Ranged AD to a point where he/she won't die. After that go for the Ranged AD (with no AP and no support left, this will be the easiest to accomplish). After all that, just clean up the other 2, generally a tank and jungler.

~~EXCEPTION~~
If they're fed, it will be much, much harder to do. Plus if you have less than a 1.0 KDR on top of that, im surprised you haven't surrendered yet.