You have to buy 5* players on the transfer market and train them up to 6 or 7-star level. Or you buy a 6* player on scout list and train him until he becomes a 7* player.
When you buy 5-star players you should check both market value and the player`s salary as it has a big impact on his training speed. Here is what I am talking about
:
http://forum.topeleven.com/tutorials...ers-chris.html
So if you are in lvl 3 now for example and want to buy 5* players who train fast you should look for a 5* player with a market value over 5M...guys with MV of 2M or 3M improve very slowly and it takes too much time and too many green packs to train him up.