https://snipboard.io/DPRx1z.jpg
My team's average is 121% with a focus on white skills and I haven't paid anything. I've spent some 6-7 seasons actively watching ads and only using energies on youth academy for CM/CDMs and GK.
Every season you can then manage to create 1 beast that afterwards you just need to maintain. On the topeleven Reddit just looks for fast-trainers and you'll find more info.
In short, join an association to get tokens, use tokens to buy 18/19 year old players below 60%. Assign a skill to train, train them using counterattack or gym (whichever he's worse at). If he gains at least 2 times out of 3 time that you train him 2 points for the skill (say, freekicks) then he's good. 1-2-2-2-2-2-2 even better, but 1-2-2, 2-1-2, 2-2-1 is all acceptable.
You use 700-800 energies, sometimes more on 1 such player to get them to 140%. Afterwards just maintain him until he's 25 years old, it shouldn't cost much. Every 1,5 season or so, build a new beast.