I played Link all Melee, and I'm working with Pit now, so hopefully I can help.
If link stand still, he can block your arrows, as they said. curve it at his head/foot.You have a stronger projectile game at range. Your arrows fire faster and longer and have better control of their direction. If he insists on playing the projectile game, stay back further. Use your down-B to reflect his projectiles and your forward-B if you're close. It reflects too. If his bombs are really annoying, practice catching them
That'll annoy the crap out of him. It's pretty tough though. Bombs are usually pretty predictable, and most of what I used them for was getting people to move where I want them. Just stay back when he has one and he shouldn't be able to get you. You'll have enough time to move. Arrow spam to pressure him into throwing it (preferably while staying in the air).
The scariest thing about his projectiles is stealing your third jump. If you get hit out of it you're toast. Not much to say on that one. Just be careful.
His long reach can be countered with a good defensive game. Shield/dodge well and it'll leave him open with his laggy recovery from most moves. Link is a lot slower than Pit. Use that to your advantage. It's easy to punish him on lag.
Beware of his shield game. Shield grabbing and spin attack out of shield are **** (and his up smash is good now too). A good Link ought use these hard. Your best bet out of a shield is probably shorthop forward and f-air or perhaps short hop backwards to arrow (if you're too far to shield grab).
Try not to take on Link if he's above you. Pit's up air will get eaten by Links d-air (at least I would think). If you come in above his kicks you should be able to get shots in on him more than you take them, as it would be difficult for him to land an u-air like that.
A last thought on projectiles. Be careful reflecting at close range. It leaves you very open if Link doesn't get hit by it on the way back. I definitely recommend the forward-B for that to help keep him from launching a counter attack.