If you want to make your whole team stronge, play friendlies...

If individual player stronge then Training...

Playing friendly has many benefits...

1) 1 Green Pack if you make a substitution...
2) 2 Morale Pack if you watch and win the game...
3) 1 Red pack if your player does not gets a card...

And the most important your whole team gets condition bonus at half time and after the end of match...

Half Time Condition Bonus = 4...
End Match Bonus = 5......