How to improve at blitz chess ?

I've been playing well over 1000 blitz games on various chessrooms during the last 2 years yet my blitz rating stays more or less the same -  and I don't know how to improve it.

Meanwhile my standard rating for long time controls improved by almost 200 points. In this games I have time for a "blunder checks" before every move and when there is intense piece contact for a systematical calculation. So the move selection process is completely diffrent and reading books / doing analysis did help to improve it.

At blitz things remain the same, sometimes I still even blunder pieces and lose to 1-2 move tactics. Solving lot's of tactical puzzles didn't help much.

Is there a way to improve blitz chess strenght, maybe a specific method to train or something ? And when you play blitz, do you perform any blunder-checks or calculations or do you select the moves by intuition only ?

You need to gain more experience, and maybe develop a specialized opening repertoire to become stronger at blitz.

Familiarity with the opening and the resulting middlegames is important.

Thanks for the replies. Opening knowledge improvement seems to be a good idea, infact i've been changing opening systems a lot in the past and maybe that's one of the reasons for the lack of progression in blitz. Will try to stick to my current one.