If you want good and fast profit, then you should invest in loaning and of course gambling sites, thus they are very very risky so you can lose all your money that you invested and if you want slower profit but no risk, then just by bitcoins and keep them in your wallet for some time and sell them when their price is very large, you will get lots of profit too
If you want a good profit then remove that "fast profit" mindset but rather sure profit.
All investment must taken step by step. Put some work, work hard, work properly etc. rather than desiring for a fast earnings with just a less work.
If you are planning to earn money with shortcut method then it will surely lead you to disaster so its better to move on in slow and steady way instead of choosing fastest ways to earn it and invite loss.