I was having the same issue. I don't remember seeing one particular trick, I found elsewhere, on this thread so I thought I'd share. If you put the middle of your ear to the top right corner of the phone, it's way louder. It's still an issue, but I've had a phone that you had to shove into your ear to be able to hear the other person talking, or if there's any relatively loud background noise, forget about it, and I don't want to relive that. I'm actually not even on the phone part of the phone that much. I'm thinking the next update will make the earpiece volume...more functional.
The external speakers are very loud, WAY louder than my Galaxy Nexus ever hoped to be. Everything else about the phone is top notch, and OH the battery life, so good.