Hi baccilus, that's what the matchmaking is for. To match you with opponents of your skill level. I suggest you sign up for prime and then play the game. You will soon be calibrated to a skill level that is appropriate and get time to improve. Also, try deathmatches more often to work upon and improve your aim and movement etc. There you can simply play without pressure of winning etc.
There are other game modes for fun as well. If you really want to improve, watching pro games with proper commentary would certainly help.
Followed your suggestion and I have been enjoying CS:GO like never before.