I used the now jade spa for both hair and makeup for myself and my bridesmaids. I definately recommend bringing pictures of what you want, and if you can swing it a trial might be helpful. If not, I recommend leaving some extra time on your wedding day in case you want to make any adjustments.
For my hair, she was right on with what I showed her in a few pictures. My makeup, not so much. During my trial I didnt bring pics of what I wanted and I said "just do a smokey eye". Well, their version of a smokey eye and my version are very different! Even though I'm really good at makeup, I didnt want to have to do it on my wedding day, so I decided to take my chances again. On my wedding day I brought pictures and she did exactly what I wanted
If you're used to using higher end products (HD foundation etc) I recommend bring those as well.. Hope this helps. theres some pics of my hair in my Now Jade gallery under my profile