How do i improve at blitz

I feel like I'm very confident playing rapid chess and i just got 2000 rating on puzzles but for some reason blitz makes me play like absolute dog water so what's some advice you experienced players can give me to improve with faster time controls.

Note: this is my new account i deactivated my old one so i don't have many games of blitz played on this account 

The puzzle ratings aren't like other ratings.

When you play, you aren't in competition with other players.

Your 543 blitz rating is not "dog water". The blitz average rating is only 630. Your rating is better than 10 million other players.

Avoid overly complicated or speculative moves that require a lot of calculation. Focus on solid development and maintaining a sound position.