Physicals (Speed and Strength) are random.

The rest got a soft of the following with a chance to go higher.

5.0 star talent = 20
4.5 star talent = 19
4.0 star talent = 18
3.5 star talent = 17
3.0 star talent = 16
2.5 star talent = 15
2.0 star talent = 14
1.5 star talent = 13
1.0 star talent = 12
0.5 star talent = 11

With a supporter account, you can tell when you've reached a player's physical caps. Otherwise, you have to just train physicals and watch to see if a number stops increasing. Also, GI Management Studio might tell you when you have hit a physical cap.

After you reach your maximum for a non-physical skill, improving on that skill becomes random instead of guaranteed. So, after accumulating 100 training points, the following odds determine whether the player will gain a skill point:

If a player is at his maximum then he has 1 in 3 chance to gain a point/level.
If a player is at his maximum + 1 then he has 1 in 5 chance to gain a point/level.
If a player is at his maximum + 2 then he has 1 in 10 chance to gain a point/level.
If a player is at his maximum + 3 then he has 1 in 20 chance to gain a point/level.
It is impossible for a player to go more than 4 above his maximum.