It's no brainer that the long term coin is the one which has huge market capitalization otherwise it's gonna have such huge volatiltiy that within days the price could change drastically.
You just should stick with major coins if you really intend to invest for long-term or do staking at the same time while waiting for another bullrun.
Also, you need to consider how healthy the people behind a projects are and what I mean by that is their planning, roadmap, etc.
For me it is very important that coin would have a practical use.
It is necessary to check what have already been done, how usefull will be project and its token in future.
Now appear some cryptocurrency projects using blockchain to keep the environment clean.
Here some of them
https://moss.earth/blogI think it is very important to keep the earth from pollution.