My trading is limited to futures! A regulated market with clear rules. I trade indices (S&P, Russell2000, Nasdaq 100) and especially commodities (soybeans, soybean meal, lean hogs, feeder cattle, gold, gasoline, crude oil, and much more). The futures market should of course be very liquid.
I won't explain here how futures work. There are many good sites that can do this better. Many people claim that futures are too risky and should be avoided. I can only disagree. Of course, the stock market is always a risk because it is unpredictable! But everyone who acts on the stock exchange should know the basics and be able to assess the risks. One should know the possible risk one is taking with the position and on be prepared for possible extreme situations!
For example, if you trade the S&P500 E-mini, it shouldn't be a problem to get a 10% move against you (e.g. Flash Crash on May 10, 2010) But there are also other extreme moves such as Brexit Crash on June 24, 2016 or the Swiss franc on January 14, 2015. Of course nobody wants such a situation, but it will happen to every trader sooner or later. The weak and undercapitalized traders will then be gone from the market.
The only thing that helps here is DISCIPLINED MONEYMANAGEMENT!