CSGO wouldn’t be itself if there weren’t multiple skins you can use when playing. So players are faced with some difficulties: how to get more and more skins so that the game would become more enjoyable?
The old fashioned way to get these skins would be to wait for good drops while playing Competitive or Casual matches. You could also play Idle servers, but it is still limited. Usually you will get around 4 drops per week and there is no guarantee that they will be the ones you need.
Another way, which might cost you money is buying the required skins. Of course, you should keep in mind, that some of the skins are quite expensive (there are some for 75 $ and other for 400$ or more).
There is another way, which is not used that much: betting. You can bet a few ways, like try your luck at a roulette or try to guess which professional CSGO team will win a match. This will require a bit more knowledge. After all, you should get to know the playing teams, learn their strengths and weaknesses and think how they will perform when playing with others.
Betting on professional matches might be a little difficult at first, but once you get to know the teams better, you will make better decisions and eventually win more skins.