Well you should learn some Technical Analysis (TA) to start, even though I feel like most of it is just educated guesses.
You should be able to research and understand what's going on with coins as far as development, community, block rewards/mining and adoption. Those are by far the most important factors in my opinion.
TA is all bullshit in crypto if you don't understand the fundamentals of a coin.
Learn how to use good stop losses and target exits.
But honestly dude, crypto is so hard to trade, it's way easier and more profitable to just buy and hold rather than time these wild markets.