...so first you screen the coins, how? You get signals from somewhere? Where? If I tell you it will invite competition.

First, every actively traded market bounces. Second, It is very possible to make more from short-term/small moves than trying to hit home runs. Entry points can be difficult to time, you can usually start buying slow and get a better deal asap using limit orders. With experience you can get a feel for when it's time to buy more aggressively, due to a legit chance of missing a big one. Learn to actually Buy Low & Sell High and please don't be stuck thinking HODL is always a good plan. Good luck with your bright future.