I hope this question hasn't been asked already, but it probably has. I have a question about planeswalkers since I'm new to using them. I know planeswalkers aren't considered creatures, so they can't be destroyed normally, but they seem to be somewhere in between creatures and players if I'm not mistaken. The rules say I can't target a planeswalker with non-combat damage directly, but I can redirect damage that would normally be sent to an opponent as the spell resolves. My question is how would I formally declare the redirection in a tournament setting?

in terms of tournament practice, you can just say something like "bolt your planeswalker" and it'll be unambiguous. technically the damage is redirected as it's being dealt, so until then you don't have to commit to it and your spell is technically targeting the player. if you want to be sneaky, you can say "bolt, targeting you?" but if you do I think you probably should follow it up with a request for responses so they know that once they pass back you have some effects, in this case a non-obvious redirect. this can be useful if you fear counterspells, for instance, to not give them undue information about your intent.

Me: I cast Lightning Bolt targeting you.
Opponent: Ok, it resolves.
Me: As it resolves, I redirect the damage to Jace.

Sounds simple enough, it seemed like a silly question but I just had to be sure. So to sum it up, target the player, and after they accept it but before the damage goes on the stack, declare redirection. That's what I thought, but I wasn't sure if it would cause confusion.

to be clear, the damage doesn't go on the stack. combat damage used to, which is probably how you picked up the term, but now even that doesn't. you declare the redirection as the spell resolves.

It would be a mistake to consider PW as being 'somewhere in between creatures and players': PW don't suffer from summoning sickness, and they don't have life points. One could as well say they are somewhere between enchantments (because they are colored permanents that can't attack nor block) and artifacts (because they have activated abilities).

It's much better not to wander around in such confusing comparisons and see PW for what they are: a full-fledged type of card, with similarities and differences to each of the seven other card types.

I believe they were meant to represent another player coming to help you out as you are suppose to be a planeswalker when playing. Also if they turn into a creature they do have summoning sickness (like any card) unless otherwise stated.

The easiest way for me to grasp the entire damage and prevention thing is that it would be too much work for them to go about and changing all the old cards that damaged and prevented damage to players. So they did it via the rules.

They're meant to represent planeswalkers, not players. You cannot cause a Gideon Jura to lose life.