That depends on your play style... If you focus on defence, maybe increase those, attack then increase those. And if you're Arsene Wenger keep Physical 10Q higher than rest

Jokes aside, I feel fullbacks need a .4Q more for physical compared to attack amd .2Q more for defence compared to attack. If you prefer to counter, maybe train Physical more, since counters need speed. If you play 4-2-3-1 more, then maybe you can focus on defensive attributes of the MCs since it's worthless to field DMCs. Increase the attack and physical attributes of your wingers, they are a must in your lineup and lately have been scoring a lot of goals. For DCs and GKs you may opt to have less attacking points, and focus on their defence the most. But don't have a difference of more than 2Q between highest and lowest. So maybe a DC has DEF 41 ATT 39 PHY 40. In the mobile version all cones are auto assigned so tick all in such a scenario. Training only a particular skill is not recommended; strikers do defend and defenders do score goals.