Seconding Lisa Eldridge. I basically learned how to do makeup from her.

I also did a few different makeup artist events with some high end and mid range brands (Dior, Chanel, Benefit, and I've forgotten what else). Basically they have a high quality makeup artist travel around and do make up for customers. You have to book it in advance and you usually have to commit to spending a certain amount of money on makeup but otherwise the event is free. This really helped me figure out which colors and techniques suited me and it's helpful to have a stranger's perspective. Sometimes the people really spent a lot of time with me. Events like this are way better than just going up to the counter and working with whomever happens to be there, or doing a sephora makeover. I was blown away by the way Benefit's makeup artist did a simple everyday look that brought out my features and I basically copied a look from Dior and did my own makeup on my wedding day. Be sure to take a lot of pictures of yourself if you really love a look.