I know a lot of people who quitted their day job to trade in the cryptocurrency market.
But it was when the market was good.
In this bear market, they're struggling very hard to survive.
So I think the best way to invest is this :
Have a side job, cut down your expenses, then invest 10-20% of your monthly income in the market.This way you never have to worry about gain and loss and surely you have higher chance of getting rich because the market will recover in the long run!

This is how I pick a coin to hold , feel free to add more , I love to learn more.
1. The market cap must be low . 1-10 million usd , <1 could be dangerous.
2. Should be coin , mineable , not a token
3. Has been mined >50% of the total supply so we will not have to be worried of the inflation .
4. An old coin with a stable project .
Some examples : grs , clubcoin , monacoin , tx , xwc , ...
Now there are some coins I feel good : pinkcoin, xmy , burst , florin .