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.
This is one of the best ideas but I would like to add something more so that it helps you in trading. My first and foremost advice to every newcomer to trading is that don't take trading too light, it is a tough job and it needs a full-time dedication. Before going practically to trading study about those currencies which you want to invest in and secondly don't invest huge amount in the beginning, start with a little amount and randomly increase your investment if you think you.are good in trading.