Tip 1) Know that you will liky finish all 10 with 14 days before the end of the game. SO BREATH.
Tip 2) Max out Kawakami asap. Her rank 10 Massage allows you to do stuff at night after mementos/palace. Abuse this to work on night confidants, or clearing conditions for confidence like working at the beef shop twice
Tip 3) Having max social stats in NG+ makes life better. Otherwise, try to be atleast lv4 all round and the confidants you have will naturally push you the rest of the way.
Tip 4) Never let a day be wasted. ALWAYS interact with someone. If there is noone to interact with, use a palace, or work at the beefshop, Lala's, or 777 store (need to work twice at each for request conditions).
Tip 5) Look at your quick travel map. Pressing Square opens a list of people who are currently available, and if they are ready for a rank up
Tip 6) Level up the fortune teller. Her (rank 7?( ability allows you to specifically choose 1 confidant to gain boosted exp. So right before you choose one, see her during the day, pay for the boost, then fast travel to your confidant.
Tip 7) Have the persona that matches the confidant.
The ideal is to always have them level up every time you talk to them.
This won't happen all the time, but if every confidant is taking 2 or more "dates" to activate the next level, you won't make it.