In my opinion, the best way is short term trading or investing to an altcoin which has expectations for the future. But investing need information which means a lot of work. Trading needs a lot of experience. Both of them is not easy.
Trading is probably a proven way to make money but I agree it is not easy and especially not for beginners. I would suggest that beginners try sports betting if it is legal in their country.
Can't see the difference - in both cases you bet on something, that is completely out of your control. You may bet as well on anything that depends on 3rd parties (market, football players).
If you already know how to bet on sports and believe a certain team will win, etc, you can make a decent sum of money betting on sports. I just bet $10 on a total in a Basketball game yesterday and made $18.80. If I had a done that with 1000 bucks I would have $1880!
That's how many stories of gambling addicts start... In long run, you always loose.