How to use a diffuser?

Ok, well recently I brought a hair dryer with a diffuser. I've read quite a lot on the internet about how to use them but I just want to see if anyone has any other tips. What kind of heat and speed setting do I need and do I HAVE to put my head upside-down? So basically any tips for how to use a diffuser to make curls. Obviously I will be using hair product first on damp hair. I have two different ones so my next question is would it be better to use mousse or l'oreal hot curls which is like a special hair spray that helps your hair go curly. I would prefer to keep as much of my natural hair colour(blonde) and I know that mousse makes it darker and makes it look like it's wet but I haven't tried the hot curls yet so which would be better? My hair is naturally wavy so will the diffuser just define my waves a bit more or will it actually give me proper curls?
Thanks in advance x

I have one where all I do is switch the dryer part with the diffuser and than turn your head upside down and use low cool heat and dry roots than turn right side up and let it fifnish drying...it kinda woks 4 me! =]

I think you should just go with your natural wave.
Sometimes diffuser makes peoples hair REALLY puffy like a clown

I think the diffuser mainly keeps curly hair from going' all over the place & keeps your hair from getting the frizzes, but still gives it body. I believe that's why they say to bend over to dry so you can get underneath your hair & that gives it body.
I used to be a hair stylist many years ago and I never heard of a mousse that makes the hair darker. Maybe it's a special kind of mousse. I agree with Stephany though, just keep your natural wave.

Just try it at home when you have free time and see what works best for you. Theres many different ways to use a diffuser so just try it out.