it all depends on your team's chemistry, but here is a few obvious ones
CF
attack (prefer above 85 at least)
shoot (above 85, and preferabbly above 75 in power)
response jump and header if you want a player who can take advantage of air balls (above 80)
dribble acc. spd, speed and body balance if you want a dribbling forward like rooney, ronaldo. (all at least above 80)
SS
same as CF but you want him to have higher shot power, and at least 75 in short pass, and you would want him to be better at dribbling
AMF
85 above in passing
prefer 80 above in dribbling
if you dont want him to lose the ball all the time, make sure his balance is above 80, I had a huge problem with platini. otherwise just try not to dribble with him and make one time passes.
special abilties you need passing or playmaking, tactical dribble or dribble. 1 tch pass would be useful but not required
CMF
try to find a good passer above 80 in both short and prefer above 75 in long pass, balance should be above 75 in order to prevent too much giveaways
speed would be enough above 75
SMF or WF
balance (more than 80 to not lose ball) extreme Speed, like above 90, long pass above 80 (for crossing), and dribble accuracy >80 + drible spd>90,
SB
can be two different style, offensive of defensive, either ways you need >90 stamina to play the whole match not dying
offensive you'd want a SB that has >85 in speed, and >80 in long pass. attacking stats would help, prefer above 75.
defensive you'd want someone above 180cm in height, defensive states above 65 is usually enough cus its more about strength rather than positioning, >80 body balance, >80 in speed is good. the height is extremely important for defending