Freelancing can be considered as the main and as an additional source of income. The latter does not imply low profitability. Just usually properly controlling finances people extra income away in savings and don't live on them. Although it still depends on how much people earn in their main job and what specific activities. But in freelancing there is almost no difference what you do. Your income is determined only by you, the qualities of character, ability to negotiate with other people, to convince them and so on. Yes, and professionalism is important. Do not expect an instant increase of welfare.
What types of activities provides freelancing?
1. Related web sites tasks. This development of the site, a programming for the Internet resource, the creation of design, content creation, administration / moderation, and so on. The last options should be discussed in detail. The filling of the site articles deals with such specialist as content Manager. His task is to arrange interesting and cheap materials for the online resources from copywriters, which, in turn, have been writing articles. Quite often copywriters at the same time perform duties of content managers. Usually pay more, but I agree on this in advance. The main task of administrators and moderators – tracking of order, contests and promotions, communicate with users.
2. Classic programming. If the programmers only deal with the development of programs for computers, now the trend of writing apps for most mobile platforms, and under multiple operating systems. Therefore, programmers are now back in Vogue, despite the fact that the labor market in this area was crowded a few years ago.
3. Photo processing and development of 3D models. Here the work associated with graphics. People can retouch other people's photos in Photoshop or develop 3D models of products for a particular company. In particular, this involved the architects.
There are many other varieties of freelancing. On specialized exchanges you will definitely find the specialty that you like best.