When the Team Constantly under-deliver...

[t11_fan]

I find that mixing 28-33 year olds with young'uns (18-22) a good mix - 50-50%

I don't think age is that important because I won cup and CL with team which had age average 20 (one player was 30y.o., one 23, all other 22 or less in 22 players squad)

What is important then? Form.
Form is something that i think it is somehow written in your player's genes. If player has constantly bad form, you can't change it whatever you do. I've tried with blue boosters, position changing (for MC's), contract renewal (to increase wage), increase win bonus... Nothing worked. Only possible solution is to sell such player and get new one. It doesn't have to be whole team. Change only worst form players, few of them can change outcome drastically.
I've went through that, my team had 9th position for days although had strongest squad in the league. Then I sold my MC's, their form was constantly 6-7. Form of team completly changed, at the end I managed to finish season 2 points behind leader.

After 7 unstoppable season, you are due a lot of troll results. So bear with it. We all need to get trolled.

It is hard to avoid troll results, but if your team is in bad form, they will repeat and repeat. One troll result doesn't mean your team has problem.

[Jult52]

Form is something that i think it is somehow written in your player's genes. If player has constantly bad form, you can't change it whatever you do. I've tried with blue boosters, position changing (for MC's), contract renewal (to increase wage), increase win bonus... Nothing worked. .

I used to subscribe to this idea but I recently was working to develop a very skilled young MC fast trainer over several seasons and was very frustrated to see him deliver form in the 4-5 range. I decided to sell him and then miraculously he started to pull a form of 7'all of a sudden - and he's stayed there. He even delivered an 8 in an important match earlier thus week. Of course, i am overjoyed.

I am still figuring out these patterns as players develop, but I would caution against necessarily assuming a player can't change his spots.