Related advice: don't destroy balance in your life to spend every waking hour working on the theory that once you get your big break you can then have balance. It doesn't work. You burn out.
I wish I took this advice in highschool and college but I'm still young (23). I was completely focused on getting my Bachelor's degree and eventually getting a good job (succeeded btw) over having much of a social life so the cons that come with that is a bit obvious...But yeah, maintain balance.