Probably the best way to grow your Bitcoins is to save them and wait for about a year. By then the price will probably have gone up by then and you will have a substantial amount of money.
A year isn't long enough. People said that last year and look where we are now. To see big gains again people will probably have to hold 3-5 years maybe even a decade to see possibly huge returns. Bitcoin isn't going to enter the mainstream over night.