Doesn’t matter how good you are at pressing buttons, understanding the game is your key strength in Dota 2. You can stop playing Dota for half a year, but if you know the game very well you won’t drop any MMR points after you come back.
High MMR players spend hours, weeks, months, years to learn all the basics of the game. Once you understand the strengths and weaknesses of all heroes, the importance of objectives, power spikes of heroes, and the rest of stuff, you should once and for all take your place among the best Dota 2 players.
Putting an extra effort
Professional players weren’t born like this. Each pro and high ranked player spent years playing the game, analyzing replays, learning from other players, and practicing. If you want to be good at this game, it is not enough only to play the game. Watch your replays, acknowledge mistakes, fix them. Want to become better on a specific hero? Watch the best players in the world play on this hero, analyze their plays, best their plays.
Focusing on yourself
This one is not as inspiring as the previous two and kind of evil. Being selfish sometimes is necessary.
You know this feeling when you play in a 5-men stack and there is one guy, who is clearly better than everyone else? Well, this guy has to make a choice. He may keep playing with his friends and enjoy his time, or leave his friends and start working on making himself better. Sadly, this is a state of the game. Very rarely you would see a full stack of friends or teammates improve equally. If you want to become a pro one day, think about what is best for you.