trading is one of those things that you have to spend a lot of time learning it. people keep saying "buy low sell high" like a chant but they don't understand it and that's the problem. it is very easy to learn too but it takes time. you have to start hanging around in the market (on exchange) and start staring at the charts for a long time and try to analyze what is happening in the market.
and also you should always know that the markets are different from each other. for example what works for stocks does not necessarily work for bitcoin and it doesn't work for altcoins. each of them require a different set of experiences to deal with their specifications.