I've fought Corsairs many times and I am going to tell you up front that they are a not an easy army to play correctly. Their low armor is not at all forgiving of mistakes. Still, they are pirates after all so we should expect them to be more tricky and underhanded in their tactics.
Anyway, here are some tips:
-You have poor defense so do not be surprised if you take a lot of casualties from shooting (Don’t be concerned about volley fire so much though). On the plus side... you have 12 Arbalests.
Having them is a huge benefit since your enemy can not easily ignore them. Chances are pretty good that your opponent will focus their fire and send their cavalry (if they have it) to deal with them. Remember that your Arbalests can take a good amount of punishment at range but if he is trying to attack them with cavalry then you should not have a problem killing the horses (or riders for that matter) with so many shots per turn. Regardless, if your opponent focuses his bows on them then that will buy your regular warriors time to close in. If he ignores them then keep your Corsairs back (and in cover) and use your ranged firepower to force him to come to you.
-Throwing weapons. Read and re-read the rules about them. Make sure you always use them before you get into combat, whether this is during a charge or moving within 6 inches of his models after he has moved for that phase.
-Your Bo’Sun is a banner so do not make the mistake of leaving him with the Arbalests. Many players take the Peter Jackson Bo’Sun model with the Crossbow and stick him with their ranged units and that is a big waste of his points.
-Dalamyr is your ace in the hole when you finally get into close combat. Make sure he is always supported by a spear and let him loose on the enemy. If you do not have numbers when you finally get to grips with your opponent then tie up his heroes with a single corsair and let Dalamyr kill normal troops until you start getting a numerical advantage. I would also try and save his point of Might for a Heroic Combat in order to maximize his killing potential.
-On a similar note as Dalamyr, your armor is weak (yes, I already said that) so you need to win combats. Always support your shield corsairs with spears and use the shield rule for any buckler pirates that do not have spear support. Keep any extra shield corsairs on your flanks to keep your spear support from being pulled off (or to threaten the enemy's flanks and pull their spear/pike support off.)
- As for your list, it looks good although there are two things that I would change. The first is I would take a few more corsairs with shields at the expense of some with spears. That will enable you to better protect your flanks and it also accounts for casualties from arrows. The other change is you are terribly low on Might right now and being able to take the initiative is paramount. I would drop the Bo'Sun for a Captain although… a Bo'Sun is very useful to Corsairs since you really need to win combats (said that already too). Given that fact… I’d drop some Arbalests and regular Corsairs to fit both in. You are still a tad low on Might for 500 points (it is a 500 point list right?) but you should have enough to get you by.
Anyway, hope that helps and good luck!