What is the best way to develop regens and why do some not work out?

I've been experimenting a bit with 15 and I am still really none the wiser. Is there a rule of thumb when buying regen youth players? For instance, I have the editor installed and I have been using it to see exactly what my players are made of. I have bought a few under 19s for my youth squad and am working to develop them in-house ready for the first team. I have been quite picky. But sometimes, even when they are played regularly they will not develop as they should.

So what do you look for? I always thought it was important to have a high determination and work ethic, and not to be injury prone to prevent that all important development at the early stage. How old does a player have to become before they stop improving? I have 19 year olds whom allegedly have reached the end of their ability tree - yet according to the editor they still have plenty of room to improve. So what gives? This is with 20/20 scouts by the way.

Do you loan them out if you are a top club or do you keep them in the reserves if you have top training facilities? What do you do?

I tend to look for the same things in my younger players, determination and no injury proneness. However if you are signing players at U18 you can always get stung, I used to sign U17 players on the regular but now I've basically totally given up on it because the players rarely amount to anything. At times this is just down to pure luck as loads of players never progress and meet their potential in real life, other times its because of injuries or consistent poor form.

In regards to staff opinions remember those opinions are based off the size of your club (and that the staff aren't always 100% correct). So a three star PA player for Man City would be a 5 star PA player for a mid-table EPL team because of the different needs of both clubs.

With my youth players I either get them in the first team early or get them loaned out, basically as soon as they are qualified as home grown I either first team them or loan them. I hate having them rot playing no competitive games. Its just Russian Roulette at the end of the day, some of the players will go on to great things, some will just never improve. Just like in real life there's no magic formula, be patient, be consistent, be persistent.

Basically just playing a kid in the first team will improve him. Training him in his specific position helps as well as mentoring. Loaning him out to get first team experience is not as effective as it should be in FM15. I've found staff opinions a lottery sometimes.

like sheriff says, there is no magic formula, but you should just take a chance sometimes and trust your instinct. if he looks good and is playing well then stick with him! form and confidence play a massive part.

also praising and bollocking him when he needs it helps!

Does mentoring them really help? I've been trying this recently and all I've really noticed a drop in determination and team work which defeats the object. I've also tried something slightly different with my reserve squad this time round. I've left some there rather than loaning them. I'll only loan if they are promised key player action otherwise it's not worth it. My youth have been developing nicely I'd say. I've got a 17 year old Scottish winger who has masses of potential and he seems to be developing nicely in the reserves. I do have exceptional facilities mind you. What is rather bizarre I find 17 year olds with world class potential who i know will be worth it and all my scouts say dont bother

Mentoring -> Its all about matching up player personalities and stats. I did it briefly whilst managing in Iceland and it was very hit and miss, but when it worked I did see decent progress in youth player stats. Especially their mental stats, try and match up players with similar base stats and personalities to avoid clashes and falling outs

Loans -> Yeah I never loan a player out unless he is guaranteed to be a full time start, like you say its a waste of time. One benefit of keeping those players at your club is obviously you can get them tutored and they will be able to use your facilities and coaches (obviously beneficial if both are of a high standard)

Player progress -> Players who are ambitious and professional will progress better. Look for positive personalities who actually "want" to reach their potential.

Mentoring/Tutoring -> Here is where you can improve those personalities or learn PPMs from the tutor, considering the tutoring goes well and their personalities don't clash (usually happens if they are somewhat controversial) Just make sure that the Tutor has a higher Determination than the young player being tutored. Otherwise the young player's determination will decrease which is something you don't want! So just make sure that there will be an increase in the player's determination or at least improvement in his personality. If none of the two can be achieved then there is no point in tutoring him "Off the pitch", some players have high determination and good personality already. In that case you can always ask to help him develop his game on the pitch - this is where he can pick up some of his PPMs (Player preferred moves) if suitable to his position & role.

Loans -> When you are loaning out a player, in the actual "Loan offer" stage make sure he will be their "Key player" or "First team regular" otherwise there is no point. Also if the club has good training facilities and coaching staff that also helps, if it's bad don't expect much development if any at all. Level of the competition also is a factor, higher level of competition resulting in better development. Generally speaking a player competing in 2nd division should be developing better than a player who is playing in division 4. All that of course if he is playing well, getting decent ratings and enough matches. Also before you loan him out, check out the Manager's "Working with youngsters" rating, ideally you want to loan a player out to a team that has a manager with great Working with youngsters rating to make sure he takes good care of him.

Natural fitness -> This attribute I see many people often overlook. Many people overlook it and yet it's so crucial to a player's career. Bare in mind it's a fixed attribute hence the term "Natural" so you can't improve it. So when I'm looking for a player I always check his Natural fitness if it's at least 11, ideally at least 14 tbh. Generally speaking players with low Natural Fitness aren't your best bet. They will still be able to perform great in a match don't get me wrong but in the long run, they will struggle compared to others. Players with low Natural Fitness will not be able to play most of the games, they will struggle to maintain their fitness during busy match schedules and it will take longer for them to recover after games which leads to those detrimental injuries and that increases their "Injury Proneness" rating respectively which greatly hinders player development.

I hope I helped a bit. Goodluck!