Hello!
Congratulations

What I can suggest is to buy some bridal magazines and go through them all (advertisements, articles, etc.) and pull all the pages that feature makeup that you like. Once you have collected all those pictures, group them into what
youthink is natural, traditional and dramatic. Then from there, you can get a better idea of what you actually want for your day of. For example, once you have three piles of pictures, you might say "wow, I thought I wanted a natural look, but I like the way the traditional makeup looks even better". Having pictures always helps makeup artists because, what you think is dramatic, will probably not be the same as what the makeup artist will think dramatic is.
Also, once you are at your preview, don't be afraid to tell the makeup artist if you don't like something. This will not hurt thier feelings (well, it shouldn't in any case) and it will help them get an idea of what you are actually looking for. Good luck and let us know how it goes!