How to master the 'ng' and 'ny' sounds without sounding like a nasal mess?

I’m obsessed with perfecting my Indonesian accent and I record myself daily to compare with native audio. However, I’m really struggling with the distinction between 'ng' and 'ny' in word-initial positions (like 'ngarai' vs 'nyanyi'). It feels like my tongue is getting in the way. Are there any specific tongue-twisters or technical explanations for where the tongue should actually sit for these, rather than just 'listening and repeating'?