Totally agree with you
The only thing I want to emphasize is number 3
3.HODL Only Altcoins With Real Use Case
There's no better tip than this one, people and devs write some beautiful whitepaper, launch a coin and try to sell to another people, but they can't asnwer the simple question: What problem you coin will solve?
They only want to lauch a coin, not solve anything, so it's not valuable in a future
The main problem is to understand which coins you have to hodl. We know a lot of situations when tokens gained so greatly that investors used to become rich people ( I mean really, serious investments here). It is very difficult to predict which of the projects will work and calculate the potential gainers.
As for another source of income, I totally agree here.