I agree, I used to get told to do death matches, but I would always just go on Youtube and find the Target practice maps!

I have been told all my CS GO life that DM was the way to practice. But it really Is not. I use about 3 different maps a day just to practice. I practice for about 30 minutes each. It has really improved my aim with all guns.

Once you know the basics and have the mechanical skill to shoot and pull down, then yes, deathmatch is probably the best way to go. Of course, if you hop into a dm (especially a custom ffa dm) and have no clue what you are doing in terms of controlling recoil, then you will get shit on. So hop into a recoil master map and learn the sprays of guns, or at-least a little bit of them. As you play you will get better with countering it. But for practicing, dm is still the best way. You can know the sprays all you want, but will that really help if you cant hit your target because you lack the mechanical skill to lock onto people and then spray. If you dm a lot, snapping to peoples bodies will come to you naturally. As well as spraying at a moving target. There are also a lot of things to work on as a player and things you will develop just from playing the game, such as crosshair placement, movement and game sense.