Yes, without practice you won´t be able to achieve anything. Playing CS:GO for an hour or more will help you gain little knowledge each day and that knowledge will eventually make you better. Therefore, putting a lot of time into the game will literally help you get better. You can practice on some of the best maps from Steam Workshop to enhance your gameplay. Aim_Botz is the best map to start with.

Stop playing on Valve casuals or DM's to get more XP, join instead some of the best community servers in your country/locality, including modes like FFA DM or Retake Servers. You can search these servers from Play -> Community Servers -> Enter keyword "FFA". FFA Means “Free For All” and allows you to select a rifle/pistol and kill any player (including team mates) on the server. Retake servers allow you to enhance your clutch skills, show you how to retake a site properly and teach you more about maps and many other things. You will meet better players on these servers than on Valve's servers for sure.
My favourite retake Server: 5.62.71.237:27015
My favourite FFA Server: 89.163.163.46:27055

Once you are ready to cross the border of a beginner, you can start playing PUGs instead of normal Matchmaking. 128 tick will be your life. Yes, I am referring you to play PUGs on your local community servers or ESEA (Paid) - America / FACEIT - Europe / SoStronk - Asia. You will meet better players and each game will teach you a unique lesson. And, these 3rd party services will allow you to track your stats including KDR, Win percentage and many more. You can even track your MM Stats using a site http://csgostats.gg

You should watch Professional gamers playing the game itself so you are updated on the latest tactics being used on the maps, as well as what things you should or shouldn´t do in situations like 1v3. Every match will teach you a great lesson and will help you to strengthen your skill set.

Everyone does a lot of mistakes, but only those who want to improve, solve them. Therefore, start downloading your matches (MM/PUGs) and analyze them precisely. You can see the mistakes you made and try to find solutions for them. Correcting small mistakes will eventually lead you to greater success.