D2Cookie breaks down his 2.9k MMR smurf Jugg replay.
Rijad originally calibrated at 1k MMR when playing with a friend. When his friend quit Dota, he decided to git gud and in 1.5 years he was able to reach 5k MMR.
Nowadays he is 6.5k and spends a lot of time making guides and educational but funny streams on YouTube and Twitch.
Needless to say, a guy who was in the trench and is now at the peak is the best kind of guy to teach you how to improve at the game!