you can earn bitcoin in a very very fast if you play in gambling, but earning bitcoin from gambling is very very risky,
That's right you can earn bitcoin very very fast from gambling but you can lose your bitcoin very very fast in gambling too. well,that is very balanced in my minds. Trading has always become the best way ever. 
And about trading , that's good idea even you choose wrong coin you still have your bitcoin not all of your money loss (cut loss)
Trading is the only way which you get an affordable risk and a change of profit. But for me altcoins is taking too much time to follow so I just trade bitcoin.
Sometimes I do particpate in ICO's
You may true that trade in altcoin for you will take long time, but I invest in those altcoins which are more active and fluctuate more faster, in that I am earning much faster , I also trade with bitcoin alone but for me it is a slow process but more satisfied.