Not being an expert is fine. You are possibly more easy to relate to if you are closer to them in learning. I believe the topics here are really about psychology / sociology and I would recommend the following:
Use the right words and phrases. Examples: 'yeah that drive me crazy when I was learning", "I didn't get x at first myself, but once someone explained y I got it, and the key was....", "That's a weird concept huh? confused the heck out of me at first, but then I realized that it was saying a,b,c"
Compliment them: Whatever they get or understand, no matter how small, praise them. This doesn't mean saying "you are doing a great job" in a fake way, rather it's that when you explain something and they are interacting with you, you praise the effort they are making and their progress "Yes, that's right, Exactly!".
Don't criticize. It's probably obvious that you don't say "duh, you don't understand x ???" but it's sometimes (or for some people) less obvious that the following language is also not good (even if true) - "This is a really basic concept that I'm explaining...", "This is really simple", "This is simple". If any of the subject matter is simple, they probably don't need the education. Don't talk down to them, but do try and talk at their level, taking cues from them.
Take initiative to 'lead' discussions and study groups. Think about setting up a lunch time group where, in a relaxed environment you can look at some code, maybe a peepcode, video or book chapter and then just discuss what you see. Better to do this "in the abstract" than to wait until you need to do it for real.