There are few methods from which bitcoins can be grown. Faucets, signature campaigns , gambling and investment.
Gambling can be risky and investment requires you must have quite big amount of bitcoins with you to gamble safe. But Faucets and signature campaigns are good method to increase the bitcoins.
Faucets are good for newbies, but it is a waste of time and too time consuming as the returns are in peanuts, so I would prefer to grow my bitcoins with signature campaigns.