When getting your makeup done for an event my first suggestion would be to hire a freelance makeup artist who will come on location to you like I do. I realize there are not freelance artists everywhere, so if you can't find one who is available or they are out of your price range then going to the makeup counter is an option. Since I worked at a makeup counter for more than a year I have a few tips to share so that you leave pleased and the makeup artist's time is well spent.
1. Choose a makeup line you like and a line where the artists makeup looks like you would want yours to look...when I worked at the Giorgio Armani counter I had a lot of clients come to me because they liked how I did my own makeup...I mean let's be serious, if someone can't do their own makeup well should you trust them to do your's?!
2. Make an appointment in advance (either call ahead or do this in person). I would ask for an experienced artist, or describe the look you are going for and ask who they recommend for you. Remember, malls are busy on weekends and makeup counters will be swamped if there is a high school dance in the area, and we all know they fall on the same 2 or 3 weekends! If you don't have an appointment you may not get the attention you are wanting, and deserve, or you may be turned away and end up at a not so great counter.
3. Show up for your appointment on time and voice your opinion before and during the makeup application. If its not looking how you want it, it is better to speak up earlier rather than later.
4. Plan to purchase 3 items when your makeup application is complete. It can be items the artist used on you that day, or a refill on a favorite item you use. Items that will be useful for you to purchase are lip products, pressed powder, and blush (these are all items you will probably want to touch up with). Makeup applications at counters are free of charge, but you are expected to purchase a few items since the artist does have a sales goal to meet, so in the end you'll probably spend around $50.
If you are a bride getting your makeup done at a counter be sure to book a consultation before the day of your wedding. You can go over the exact look you want on the day of and be sure to request the same artist on the day of the wedding if you like them.
Remember to have fun when you're getting your makeup done, it's always nice to have someone else help make you look fabulous!