I want to say that Jtails still plays Toon Link once in a while. Most other players I've seen in tournaments rely on their general skill and don't have a lot of character knowledge. Most of the good ones seem to play online, from what I can tell. I don't follow the competitive scene as closely as I used to, so there might be someone else I'm not aware of.
The big things that I would recommend thinking about/looking into:
1. Z-dropping bombs and catching them. This game has a lot of options for catching items, which helps with mind-games.
2. Attack cancelling. Toon Link mostly uses this so you can instantly throw a bomb as you catch it. It's pretty tricky to do, though.
3. Throws. Most people seem to prefer down-throw at low percents, for some reason. At 0% it can lead to jab-locks, but other than that it doesn't have any real follow-ups unless I'm missing something. Up-throw -> up-air works at low-mid percents, depending on the character, so I'd recommend that if you want extra damage and not just positioning. Back-throw is your kill throw.
4. Neutral. Toon Link is more complicated neutral than most characters. His projectiles are a big part of his game plan, but his big damage comes from his sword, so ideally you would use projectiles to either confirm into close combat or to manipulate people into a situation that limits their options. Don't be afraid to back off if it's not safe to push your advantage. Tink is fast enough to get out of Dodge in most situations if you don't overextend.
5. Kills. He has a lot of kill moves, but most of them aren't going to happen much without confirms or conditioning. I'll let you look them up, since that's something a lot of people covering Tink will cover. Up-B is excellent, though. I believe it comes out at frame 6 on the ground and kills close to the ledge as early as most things. Usually, kills can happen between 110-130%. If it's just not happening for you, I think up-throw starts killing around 170%, but I might be conflating data from Young Link with that one.
One thing that I find weird is that Toon Link probably has as many combo tools as Young Link, but they are all situational, so it's fairly easy to get 40% combos in training mode, but it won't happen as much in actual matches. I think he has more room to grow than the other Links, so have fun figuring stuff out. If you have questions or want to talk about something, feel free to ask. I get the feeling a lot of us lurk pretty frequently, even if we aren't posting much.
