Art commisions. :p
That's probably not something you can just hop into though. Nor is it very profitable.
This might or might not help you though.
That is an ad
Hmm, that's not (quite) an ad, although (surprise!) there are plenty of ads on the site. Although it is a bit scummy - they're trying to imitate lifehacker.com, which is a pretty good site in general (and they fooled me at first too). Sometimes the articles can be a little superficial, that's often alleviated by good comments. That article was nothing super special, but it *was* a decent brief overview of a few ways to get started. How much do you expect from 1 article covering 24 things? Books have been written about each of those approaches, it's kinda up to you to do more research on the ones that sound attractive to you.
Here's lifehacker's version of an article like that (2012, but still should be mostly applicable):
http://lifehacker.com/5952900/how-can-i-earn-some-pocket-money-online and mroe recent
http://lifehacker.com/this-graphic-lists-over-200-resources-for-making-money-1609553725And yeah, the big question is "what skills do you have" - although there are a bunch of whimsical gigs on sites like fiverr and the like, you'll get more steady jobs/higher paying jobs in areas you have some skills in. Translating from other languages you know to English might be one?
One potential pitfall - how are you planning to get paid? I got the impression you're not in the US, and even in the US paypal makes you jump through hoops to "validate" your account once you start receiving more than a few bucks, and you're supposed to be over 18 and have a bank account to link.
I'd suggest at least trying out fiverr, or whatever similar site is "hot" now. Register, look at the gigs other people are offering, put up a gig that you're willing to do for $5 (figure <$4 after their fees), hope someone buys it, do the work, buyer reviews it, if no dispute you get $4 or so.
These are called "micro gig sites" or "micro job sites", and there's a ton - Fiverr, shorttask, SeoClerks, tenbux, MyCheapJobs, Gigbucks, Fourerr, Zjobs, Yooker, etc and etc.
For bigger jobs they are called "freelancer sites" - freelancer, upwork, guru, there are hundreds of these too.
ED: Oh yeah check out this reddit too:
https://www.reddit.com/r/beermoney esp the Getting Started and FAQ