Even tough gambling is too risky, but I think gambling is better for me to grow my bitcoin than trading (waiting the price up or down sounds boring for me 
)
)You got it lol. And trading can considered a slow type of gambling too so the bottom line here is ; you still gambling while doing trading. Im not rushing to boost my coins but I preferred (as of now) gambling through sports betting than waiting for the price to become roller coaster then do the buy and sell method.
The is only one thing that I would do to grow my Bitcoins, and that is to invest them in a reliable company or shares. The way I would reach ROI (it could take longer than expected) 
I think thats a way to grow your money, not bitcoin