Take deep breaths. Quick tip I use is I see a move a
Rapid - Slowing down and using my time wisely

...move I like but before playing it, try to find a better one. That helps slow me down, especially in the middle game with so many options
In a 15|10 game start at 40 seconds per move and finish on increment at 10 seconds per move.
You then finish at half the speed of a blitz game.
Time is a resource. Use it to find better moves. Always check your intended move is no blunder before you play it. Shallow tactics that work in blitz do not work in 15|10 rapid. Flagging that plays a major role in bullet is impossible in 15|10 rapid.
I really enjoy some of the faster formats: blitz and bullet. I desire to play longer formats like 15|10, but I always find myself rushing as if it was a 3 or 5 minute game, which I believe a lot of beginners who play faster time formats fall into. Are there any tips to slow down and use my time in rapid games.