How can I improve my middlegame in chess?

I’ve been trying to improve my middlegame in chess, but I feel like I’m stuck.

Do you have any tips, resources, or exercises you could recommend? I’d really appreciate any advice you have!

Thanks a bunch!

Thank you, so first I will develop my pieces and then castle

Learn and apply the most important principles of chess. - (core of my teaching)
Always blunder-check your moves.
Solve tactics in the right way.
Analyze your games.
Study games of strong players.
Learn how to be more psychologically resilient.
Work on your time management skills.
Get a coach if you can.

Depends on where you think your weak points are? Are you overlooking pieces under attack? Are you getting hit with pins and forks from your opponent that you didn't see? Are you getting to a decent position out of the opening and then having no idea what to do next?

If the first, then take more time going over the board, looking for your undefended pieces, and looking at what pieces your opponent is attacking now. The second is similar, but you look to see what your opponent could do after a move, so not what the board is right now but what the board would be if your opponent gets to make a move instead of you. The third is trickier. If I find myself in a position where things look good, but there isn't any obvious tactics available, then I sometimes find my thinking just collapses and I have no idea what to do next. I can find myself desperately looking for an attacking move to try and force something to happen, thinking that I'm just missing the winning blow. That is almost never the case though.

What I'm working on in those situations is to take a moment, and start looking for less immediate things but rather ideas that might require a bit of time to achieve, such as are there any outpost squares for me? If so, how can I get a Knight there? Or, I have a light square Bishop and they have a dark square Bishop, so I should start trying to put pawns on dark squares. Or, their Knight/Bishop/Rook, etc is a bit stuck and not doing a great deal, what squares does it need to get to in order to get back into the game? Can I control those squares?
In other words, in the middle game, after a successful opening, it may be that the next phase is more about implementing some ideas about how to make your position better while making your opponent's position a bit harder. Eventually, those ideas will lead to tactical opportunities.

Anyway, it also may just be that you've reached a temporary plateau, and as you fine tune the information and knowledge you've learned, it will eventually calibrate itself properly and you'll start your next climb.