Your post made me laugh because I found myself in the same situation when I was studying abroad in Granada.... my hair pretty much got so bad eventually that I had no choice and had to go. I speak pretty Spanish but was terrified. I asked my Spanish friend to recommend a salon, and then made her come with me. Well this was great until we got there and they made me put this robe on over my clothes and took me to a different room! I think the place I went was pretty average, at least it seemed that way from the people in it!
It was an intersting experience to say the least!
I didnt even have a photo, it would have been a good idea. I tried to explain what I wanted, I'm sure I wasnt using the correct terminology but with enough describing I think they got it... for example I wanted the part on the right side, well I had no idea the word for part so I just said "la raya", probably not the correct term but she got the idea. You get the idea, just do a lot of pointing, etc. In the end, I ended up with a pretty decent haircut! Maybe thats because beyond the baisc, how long, layers etc, it was pretty much in their hands
Some vocab I have learned since that first study abroad experience 3 years ago that you might find helpful...
-layers are called "capas"
-sideburns are called "patillas"
-even it up- "emparejar"
-a trim is "recortar"
-hair dye is tinte or tinto, something like that.
hope that helps a bit!
kelly