It'd be interesting to know how people find and analyse good long term projects that made insane profits. Can you list:
1. How you found the coin
2. Why you believed in the project
3. Why are you still holding or why you sold
Marketcap will tell you some information about the project and the type of coin, although it doesn't have very good expectations and opportunities if investing in the coin, but basically marketcap can be some reference to get started.
In addition to outside information about the project, of course there is a self-assessment to make an investment, for example: I did that on ADA coins two years ago, the results were able to buy some of my personal property.