Favoured Personnel

I was just asking, how do you become a favoured personnel quickly to a player? and does it help if i leave my current/get sacked, and try to get them in the other one? It's just i have some youth in my current club and it will be annoying if i had to get them for 30M in the future if i plan to leave

Praise them when they do well, call them out when they don't play well (they really like this for some reason), and tell them they are getting rested straight after a game, even though you may not intend to.

Do this every 2 or 3 weeks. Play them as often as you can as well.

Praise them in a private chat whenever they do well. My rule of thumb is to always praise my players for their last performance if they get 8 or above in a match, and at the start of the month praise any players who have an average rating of 7.5ish for their recent form. Those numbers are flexible because it depends on the level I'm playing at - those numbers worked for highly professional players at Dortmund, but I found I could lower them when managing Grasshoppers in Switzerland.

After about six months I'm normally in quite a few players' favoured personnel, and in most of them by the end of the season.

I don't think that will necessarily help you get a bid accepted for them, but it should make them more likely to want to join you if you get to the contract negotiation stage.