The way of playing, depending from your goals and the sources you can have (the min. from the game, buying, farming, downloading apps).
If you can buy one season 5-6 fast trainers and the next season another 5-6, having 10 fast trainers, you can keep them at 6* for 5-6 seasons -2 contracts. From 18-20 and 21-23. You can have more, but that means you need extra packs, so a solution is to buy one season some players, 5* veterans, old and cheap, and maybe sell them the next or in two seasons. Those players can use them in games or friendlies and don't train them.
I have every season a team that starting from 5* and finishing at 6*. With this quality, many games of the season are easy. Almost half in my league, two with a weak team in my CH.L. group and depending what's gonna be in the cup. So, in those teams you can use the 5* veterans and keep the 6* fast trainers for training and maybe one game.
Give green packs only to fast trainers to train and use the veterans for games and maybe some friendlies.
Then, in CH.L. knock out rounds against high quality teams, use your higher q fast trainers adding some veterans who are in good form and removing some youngster who are not in form.
* you can't go for the three competitions because the Cup needs a specific method to win it.