1. You need to develop strategy
2. You have to safely check this strategy.
For this you need some back-tester either developed by you or bought/taken somewhere
The other thing is data. You have to feed your back-tester with historical data to asses if the strategy above is successful.
If not - redevelop strategy till it satisfies you.
3. Even if you have your working method of trading, it's better to be careful, when trading in real market.
It's full of unpredictable movements, so keep caution.
You may also refuse volatile speculation (known as trading) and become an investor.
It's safer, requires less efforts and which is more important less nerves, but that doesn't mean, that it's easier.
For this you should learn coins you want to keep, split your investments (Don't keep all your investments in one direction /coin)
and go on. Practice makes perfect.