When people ask how we can increase our bitcoins, so i think that may be they are greedy, so choice the gambling may be it will be suit you and within day you can earn one bitcoin in a day. But gambling is Luck by chance and if you will win so also you will be lost, so prepared your mind and than play it. Otherwise it is risky. secondly trading is also best , but if you have skills and knowledge than should do it, otherwise trading need brain, and skills than of course you can get profit.
But the easiest way it saving, mean you should save your bitcoins and when you realize bitcoin price is increasing so selling it and get profit, and when ever price down than again buy the bitcoins and continue that way.