Here are few methods to make money on a side if you are in need of an extra income source. Some of this methods can provide you with enough to live off it. I do freelancing full time, so I know what I am talking about ;)
Here are sites that pay you to review websites and products:
You can make a good income source if you are fluent in English and you like to talk/write. This job is not demanding, and you can make a good income by doing 10-15 hours of work a week (if you can grab a lot of gigs, you can make easily $200-300 per week or more if you are dedicated and fast working).
Some writing services - some of them offer reasonable rates for writing articles. Again, depending on your requirements, you can make some nice money out of them:
In most of those services, you start low - by writing cheap articles for SEO. But once you create a dozen or two of articles, you can be promoted to higher earning tier. Each of these services is different, so you will need to study their rules. Entry level writers usually receive around $200/week - this grows fast with positive reviews and portfolio.
If you have a skill in designing, then try this:
While there are many more sources to find a job as a freelancer, I think those above are sufficient to get some extra income fast. Freelancer is the largest platform probably. It has mixed reviews, but there is a trick to make sure you get paid and not run into issues (if you have no experience in freelancing) - only apply for jobs from the US/UK. Usually, those markets are worry-not as long as you deliver quality designs and are suitable for people that just started freelancing. The second tip - never try to be a bottom feeder by setting low prices - this will end up with working with some very demanding customers that expect from you to work for close to nothing.
Get hired as a developer:
As with designing, if you are new to the freelancing, focus first on applying for jobs in US/UK markets and do not do race to the bottom with pricing. Often customers that pick lowest prices turn out to be very demanding and problematic. They sometimes even expect you to work for free on some extra work holding your payment from original work hostage until you finish it. Until you get more experience, it is better to stay out of complicated gigs. Just be prepared to send dozens of applications before you get the first job.
If you cant work in any of the above there is micro working communities that can make you few bucks here and there:
You cannot expect much money from them. If you are active and you spend your free time on them, you can realistically expect to make $75-150/week. It's a non-demanding side income.
Do you have more links/ideas? Share them in comments below!