No need to read all those outdated posts just to find "the best drills". Some posts are good tho such how to spot fast trainers and the golden age to gain stars, but not that many.

All you need is power train. Use 6x GK drill at once (it's up to you how many times you wanna train your players by using this drill and, of course, how many green packs you have) and use any Hard drill for the last training, the more level drill has, the better result you can get.

The current gameplay is pretty f***ed up. I have many loss against teams that only have maxed out fitness and speed while the other attributes are at 1%. The match engine can only read 340% as the maximum attribute. So it's kinda useless to have more than that. Now you know what are the attributes you need to focus on.