I have a photography instructor that I trust and respect. From time to time, I bring him few of my work and he gives me his opinions - good and bad.
I do not do this on regular basis though. I usually make contact prints and look through. Try to print what I like and see how they come out in the end.

I also have a girlfriend who likes to look at my work but she is non-photographer. Sometimes, non-enthusiasts opinions do help.