hey mate.
this game is a long term investment. it will take you years in real life time in order to have a world class team...
I think you are on the right path. Looking at the guard you are selling, it is clear from the pops he received the last 2 weeks, that you know what you are doing and that you are training the right thing.
Make sure you spend as much as you can into scouting, when I started I was able to afford 20000 a year so I did.
At the beginning of the next season, alot off new trainees will be put on the transfer list. I would suggest to buy players at atleast star or all star potential and train train train...
Good luck and feel free to ask anything you like to know. I am not an all knowing oracle, but I am doing quite well and am building a very nice balanced team...