How do I stop my 'sj' sound from sounding like a generic 'sh' to my relatives?

I'm a heritage learner and my Swedish grandmother constantly corrects my pronunciation of words like 'sju' and 'sked'. I feel like I'm doing the tongue placement right, but I suspect I'm over-articulating the 'sh' sound and missing the Swedish fricative nuances. How can I practice getting that sound to blend naturally so I don't sound like a tourist in my own living room?