I had the most fun ever when going in blind. I will only go read up on something once I beat it OR if I can't get passed it(and even then I prefer to try to train it).

If people leave when you mention you're new then really you're better off not being teamed up with them. I know when I was leveling CNJ/WHM I always stated on each run that I'm new to healing that run. I did the same as DD.

I still have an utmoste respect for someone that I ran brayflox longstop with and the whole party was polite but they didn't tell me the mechanics - let me figure it out on my own - and to this day is still one of my favorite dungeons because of it(nobody spoiled it with you need to do this, that etc...). So when I run as a high level a low level dungeon I will only help with explanations if I see the rest struggling. But in general will leave them be other than hi - and so far has always worked out.