I often find messages on the forum from people who want to earn extra money on the Internet while their crypto investments are growing up. And in most cases, they don't have the skills for remote work or freelance work experience. 
It seems to me that the community can give them some tips for more realistic perception of such earnings.

I can say the following based on my experience:
You need to understand, in the first place, that learning any skill takes time, and you won't have a quick income. Many fall into this trap, believing that they can earn money quickly on the Internet by taking a couple of courses. But you can try to start a freelance career. I would say, that has studied the skill at least at a basic level, you will be able to count on income in at least 6 months. But you have to work and develop your skills every day. It all depends on what you have a predisposition to. You can try to learn programming skills or become a quality assurance, a profession easier to enter.
If you have an interest in design or illustration, you can try to become a logo designer (and start at a contest on 99design) or vector illustrator on stock (Shutterstock, Adobe stock, etc), and maybe a stock photographer too.
Or get a job as a Google SERP tester. Or HR-recruiter.
It all depends on you.

It would be great to put together a list of remote additional earnings opportunities, describe your experience here, please, if you can advise something.