Good morning,
User iracema wrote a cool guide on how to train and resell players some time ago.
(The original post can be found here: https://www.managerzone.com/?p=forum&sub=topic&topic_id=12841281&forum_id=47&sport=soccer)
It covers topics such as how to read scout reports, evaluate player worth, boost a player's value, best training methods, the right times to sell for the highest profit, among other things.
It's proved particularly helpful to new users or people coming back to the game after a break, though it also contains nuggets of wisdom that veteran players may find useful.
Recognizing its value, I've obtained permission from iracema to add some images and extra details, and have translated it into English for wider accessibility.
Link:
https://mz-guide.vercel.app/training-and-transfermarket.html
And well that's all for now.