Wow looking good there budy you potentially have a big scorer on your hands :)
considering he is still 18 i would suggest trying to train up his jump shot and even jump range a few levels this season, maybe handling/passing depending on whether you want him to be an assister or a good ball handler.
Most people i think will suggest you stick with training ID, IS and REB and forget about shotblocking because some will say its already high enough and just increases the salary. I tend to agree and his sb is already strong so thats perfect.
You will need to get his stamina up eventually though but i think for the rest of this season concentrate on guard skills and JS/JR and get them up to about inept/awful at least, maybe higher for your js. then all of next season you can concentrate on his mains and get his ID, IS and REB up a few levels.
Reb is one you have to be very careful with because you can only do it in two postions so if you have young people and wont pick early in the draft you may wish to train that up a few levels now.
you've done a great job so far :)