buy a magazine,or look on the net for celebs that you like the look of,get some inspiration.you can cut out the picture from the mag and show it the hairdresser or just try to explain the look you would like.I, for example ask for Jennifer Anniston colour. They will give you consultation for free just before your haircut/colour or im sure if you want before. Out of interest,what does your hair look like now and what celeb hair do you like?
TBH - as far as cut is concerned it is long overall (bra-strap length) and layered (a la "the MN haircut!". I like the layers, I just want to take the overall length up to just below shoulders. So that is reasonably easy.
As far as colour is concerned - all I really want to do is cover my grey, and add a bit of gloss. I don't want a totally different colour. The biggest thing that I am unsure off WRT colour is whether to go permanent (and have to keep on top of getting my roots done) or semi-permanent and just let it fade and having a little more freedom when it comes to when to get it re-done. I am leaning towards semi - at least in the first instance as it is the first time I will have done it.