Trouble with something new to me.

So I thought I'd ask the brethren.

Does anyone know a trick to making good arepas?
I've found so many different recipes and haven't had them come out the way I expect yet. I've been trying to get that hollow sound when tapped.
It's not happening, Any help is appreciated.

masarepa, water & salt. Frying them then baking for 15-20 min. I plan on stuffing them once I get them right. I saw one recipe that called for milk instead of water.