I've just started playing 2 days before last season finish and I was promoted..

I'm about to build my team, but what do I do?

I've got a strong team right now and I'm ready to buy players that would last longer than 2 seasons..

The thing is now, who do I buy? Is it possible to buy players that would evolve to good players in the long run? Or should I buy a new team every time I get promoted?