Can't be better than that...

I just can't become better... i try puzzels, tactics and i can't see solutions... i act hasily and do not see combinations after so many attempts to solve puzzels... i can't jump over 900 rating... i can't beat others... every day, when i finish my civil engineer work i try to study chess, but i don't understand many of the moves, i can't see it... what to do... ?

play long time controls to improve. short time controls for fun. Play less blitz. How are you solving puzzles? What is your method?

Also you have nearly a thousand blitz games. Are you studying chess everyday after work or playing blitz. Be honest with yourself about whether you are doing the right things in an organised and disciplined way?