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.