To put things in perspective, studying smart trumps studying hard. (not just for chess)
One fairly efficient use of time is to
1- Play a slow game against a stronger player (can't be equal or weaker)
2- Get the game (likely to be a loss) critiqued by a coach or stronger player
3- Build up a list of mistakes you are making (via step 2)
4- Build up a list of "things to remember" (via step 2)
5- Rinse and repeat => go back to step 1
This feedback loop alone is enough to keep you on a growth path in terms of strength.
I've seen beginner-level kids visit chess clubs and sponge (2+3+4) on a weekly basis and they got strong with just that (no reading or studying!)
Not saying that 1-way learning (books,videos) don't help at all .. but so this "learning by osmosis + interaction" can be quite effective if you are short on time.
Highschool is going to be so busy for me, but nevertheless I still want to continue seriously playing chess (for the federation), and studying it. I want to get as good as I can because theese teenage years are the best time for improvement. I'm 14, and I just realized that I will have no more than an hour on Mondays-Thursdays. I will have about 2 hours on friday. And up 3 hours on Saturday and Sunday. You gotta remember, that I can't just use all my free time in chess. I do other things too like card magic (check out my channel on card magic by the way: http://www.youtube.com/user/Rock545451?feature=mhee). I estimated that I will only have 2 hours MAX a day of free time during the weekdays (excluding exercise and snack). So I'm considering devoting 1 hour or slightly more to chess, and the rest to card magic and other entertainment.
But is this enough????? That's the main question. I know GM's are probably thinking (this is nothing!). But I don't have the time! And the other question is, how do I study?
How should I distribute my precious time of study?