Decide for a while on a repertoire based on the openings you already know. Keep the openings you know but do not include as backups. Start playing only your repertoire openings so you learn them better.
When an opening needs repair then decide for one of your backups as backup. If none is available then you have to learn a new as long as your main opening is at repair.
Never try to learn more than one opening at a time!
Have a system for keeping notes etc. on your openings, so you don't have to do the same work over and over again.
I'm about 1700 on chess.com. I'm currently using an opening repertoire that my old chess coach gave me. I'm trying to push my rating. I'm seeking some guidance about how to develop a more rigorous opening repertoire. I'm looking for guidance on where to even start. Although I've tried a number of different openings over the years (scotch, London, d4 for white, CK, sicilian, Nimzo Indian, Dutch stonewall), I really don't know where to even begin. Step by step, how do other people develop their opening repertoires?
Secondly, I'm wondering about lichess versus chessbase (CB). I have CB 17 but i've been using lichess a lot lately. I'm prepared and willing to pay for CB18, but when I google Lichess versus CB it's unclear to me if\how CB is better than lichess which is free of charge, thoughts?