Hi,
I play Link since a lot of time now, and i dunno really well when use which projectile and when, often, when i throw a boomerang, i get punish because the animation is pretty long, and if the opponent shield it, you're still punishable.
In general, i dunno how react when my opponent shield my projectiles, and when switch melee to projectile.
And, do you have any trick with Link ?
I'm gonna let you partially off the hook because we don't have resources devoted to your question. However, you're only
partially off the hook because you didn't use the dang Q&A thread to ask a question! I go through all that work to create a Q&A thread so as to cut back on spam threads and yet they still keep popping up. So this is your first and final warning, if you have a question, ask it in the Q&A thread. I can tell you didn't even bother reading through it because I know for a fact that the very first FAQ would've answered your second question.
And while you're at it, read the rest of the stickies.
Especially the
Link Board Rules
Alright now to answer your first question. Probably the biggest thing to remember while projectile spamming with Link is to always keep moving. The reason you get punished for spamming projectiles is because you're not moving. Learn how to incorporate jumps into your spam game, this is the best way to keep moving. Also, other mobility techs like bombsliding, JCT, and wavebouncing are great to keep in mind.
Here's some other general tips concerning Link's projectiles: (1) Honestly, you never want to catch the boomerang. The catching animation is much shorter in Smash 4, but that doesn't matter. You should always try to be doing something else when the boomerang returns. Some good options would be Zair, Fair, or a bomb pull. (2) Charging the bow is generally considered a bad idea. Charging your bow makes it easy for your opponent to block or even avoid the arrow completely. Not to mention that it keeps you from moving, and remember that we want to keep moving. If you want more range from your bow then try firing an uncharged shot from the peak of a short or full hop. (3) Bombs are great vs shields. When you throw a bomb at a shield it doesn't explode, it just bounces off. This means that it's still there to put pressure on your opponent. A lot of times, the opponent will stay in their shield and wait for the bomb to explode. This leaves them wide open for a grab. (4) remember that you can throw bombs in the 4 compass directions, and you can drop them by pressing grab in mid air. Try to learn to incorporate all of these into your game to keep things fresh.
As far as when to switch between projectiles and melee goes, you should be switching between them freely throughout a match. Things like following up a boomerang with a Zair or Fair. jumping towards your opponent while throwing a bomb and then follow up with jabs. Grabbing someone, doing a forward/back throw and then throwing an up angled boomerang. You shouldn't really think of melee and projectiles as two separate things, but rather as different tools that work together and compliment each other.
To finish it all off, here's a couple of videos that might help you get a grasp on things:
https://www.youtube.com/watch?v=zAGBn57C2NM
https://www.youtube.com/watch?v=jYzQfF0Z-e8
And seriously, read the stickies and post further questions in the Q&A thread...I got my eye on you.