not common advices, i need spesific ones..
this failed by this line i guess, you guys just have common advices probably
I'll look for some videos then, i might have seen some "from xx elo to yy elo speedrun" videos on youtube, maybe i was just seeing things 
chessvibes might have something useful
ChessVibes Rating Climb - Rapid
1400 - https://www.youtube.com/watch?v=07fgG4I6nPE
1425 - https://www.youtube.com/watch?v=EbRmBMXC0KU
1450 - https://www.youtube.com/watch?v=_Ls6z8p0O6A
1475 - https://www.youtube.com/watch?v=uhYsd1pR_Co
1500 - https://www.youtube.com/watch?v=ju0a8PdNmP4
1525 - https://www.youtube.com/watch?v=8EKVnsLmSZs
1550 - https://www.youtube.com/watch?v=N9Bu3O2ZBQA
1575 - https://www.youtube.com/watch?v=To2FGr4AZfk
1600 - https://www.youtube.com/watch?v=LlP57aCsNs4
chomp on hanging pieces and try to hang pieces less often
I consider 1,400 intermediate player.
The Advice I give to 1,400 players is change opening/lines!
Most Beginners (Players under 1,400) will play random homemade lines or they will play lines other players recommend to them as a “starter line”
When you reach 1,400, Your chess personally and chess identity is starting to form!
You need to change lines and try different stuff to see what openings mash up with your style!
not common advices, i need spesific ones..
how do you classify a 1400? intermediate? what are the most common mistakes that should be improved before 1600