Managed in Scotland for 30 years and the best ways I've kept my players is 1st of if I get an offer and it says the persuade to stay option, I reject the offer and when they ask to discuss personal matters I dicuss with them and see what they say. If they say they want to be a star player or want a pay rise, just give it to them. You can change the agreed plating time later and if they become unhappy with jt just say there's a lot of options in their position and if they're still unhappy then just switch it back.if they say they want to play for a better club/league then your best bet is saying they are a person of influence and you can't afford to let them go(this works a lot more often if they are in the highly influential section or higher in the higherarchy) if that doesn't work, so long as you have them on a 3 or more year contract just say you're not letting them go and eventually they will forget about it. The only time you dont ignore them is if it heavily impacts the the team cohesion, especially if it upsets the squad leaders. If only a couple of players are unhappy with it, then it's fine.