Thankfully, there are ways to improve your CS:GO skills and none of them require a huge amount of time or money.
Watch them play both regular matches and death matches, as that will give you hints on both ways of playing the game.
Pay for a CS:GO coach -- It is possible to hire a CS:GO coach to train you in how to be a better player.
You will find coaches advertising their services on online forums. Find one that is reputable and that has other players vouching for his training and skills.
Pay for CS:GO boosting -- It is also possible to pay for csgo boosting. This requires paying for someone to play as your character with the goal of leveling up that character to the ranking you want.
This can be done through an online boosting service and, as long as you choose one that is reputable, is completely safe. They will pay a better player to play in your CS:GO games until your character gains the ranking you need. You can then retake your account and play CS:GO as before.
Get more information at csgo boosting.