Yeah, battling really is the best way to learn. Read up on some stuff, stick six OUs on a team and start battling. You'll quickly learn the dos and don'ts, the goods and bads, and what works and what doesn't. Your first team will probably suck, but as you play more, you'll get used to the game and know what your team needs and doesn't need. Your teams will, in time, get better.
Oh, and a little piece of advice I like to add is use the metagame's weaknesses to your advantages. If you notice that a lot of people seem to have a huge Gyara weak, put a Gyara on your team and start killing stuff. Don't take this too seriously, but it's worth keeping in mind ;)
Also, make sure you have all of the essential components. A team with no walls is probably going to get destroyed by every sweeper that comes along. A team with no sweepers is going to have trouble actually doing anything to the opponent. Now, things like Stall teams work well even without sweepers, but that's because they're still executing their own strategy and hurting the other team in their own way. An all offensive team can work, too, so long as the sweepers are bulky enough to take a lot of hits or you have a Wish Sweeper (WishMence anyone?)
Basically, make a team, get out there, and start battling. You'll get better with time.