Like everything else in singing it's a guessing game until you got it down.
Perhaps listen to some gospel bass singers. The majority of those fry the very low notes, say Bb1 and down.
Or you could try the mongolian throat singers. It's a very special type of fry but perhaps imitating them will help you.
I think the girl in 'The Grudge' makes a frying sound whenever she's at large. Check it out on youtube.
Frying to me requires less muscles than normal singing, so when you attempt frying, don't imagine that you have to push or stress anything at all. You should feel vibrations in your soft palate and a little bit in your larynx.
Good luck!