Tongue position
When this happens, the center of the tongue rises higher and the sound is soft.
Pronunciation
Sh, h, sh and ć - hear the difference
Practical training for sounds that often change meaning.
Couples
Practice short contrasts: groats-Kasia, do-you, please-piglet at a controlled pace.
Rhythm
Insert a difficult word into the entire phrase to keep the accent and breath natural.
Recording
Compare your own footage with the model and correct just one element at a time.