Proper pronunciation of "ll"

I've noticed that Mauricio pronounces the double L (e.g., ella) with a "ya" sound. However, in lesson 1.9, pronunciation of the double L differs. For example, when saying "llorando" it has a "shja" sound; while "cuchillo" maintains the "ya" sound. My dad, who is from Puerto Rico always uses the "shja" pronunciation... so when he says ella it sounds like "eja", with the "j" pronounced as it is in English. How do I know when to use the "ya" vs. the "shja" sound? Thanks!

Probably the most often asked question on the Rocket Spanish forum! Unfortunately the answer isn't really clear. It seems to be a preference, or perhaps a regional thing.

"shja", or "ya" the real key is to be understood!

Thanks, jchamb. I think I will just use whatever seems natural in the situation.