The most important part of playing gangplank early in the game is to just keep farming with parrrrrrrrrrrrley as its passive gives increased gold per minion kill which when paired with avarice blade gives a huge amount of bonus gold worth almost half the value of the minion.

If getting harassed in lane the best thing to do is just keep poking with parrrrrrrley to slowly grind your opponent down and keep eating your oranges so you're K.

Remove scurvy is an awesome ability as it removes all types of CC. An example of using remove scurvy is when jax leaps on you to stun you can just use remove scurvy to get rid of the stun and heal then use raise moral to run away and ghost if necessary.

let your team initiate then just whack your ult down to deal massive damage whilst poking with parrrrrrley to grind opponents down.