Make sure you book a consultation and trial with the makeup artist – although he or she *should* bring this topic up during your initial conversation.
It is a good idea to schedule the appointment a minimum of a 2-3 months before your wedding day so there is time to discuss details and/or changes to the look you want.
The artist may also have policies in place with respect to deadlines for adding more people, etc. so you will want to keep this in mind before saying “No problem!” to a bridesmaid/aunt/cousin/mother, if they decide at the 11th hour that they want to get their makeup done on the day of the wedding.
Even if you have discussed the type of look you want before your makeup trial, it is a good idea to do some surfing on the internet (a great place to start is photos from the red carpet at the Oscars), and bring colour printouts of photos that reflect the type of look you are wanting to achieve – or alternatively, send the artist an email with links to the photos you like.
Giving the artist some visual references is extremely helpful and will (hopefully!) avoid any confusion and/or miscommunication. The artist will also be able to advise you in terms of the suitability of a particular look or style – for example, you may totally love the way JLo looks in pale beige lipstick, but it might not work at all if you have a fair complexion.
Make sure you book a trial run with your hair stylist as well – and again, avoid booking this appointment too close to the big day. The last thing you want or need is to wake up on your wedding day and still not have a clear idea of how you want your hair to look.
With both the makeup and hair trials, have the artist/stylist or a friend take some closeup photos so that you can look at them later to reassure yourself that you are happy with the results – and so the artist/stylist has an actual reference and doesn’t have to rely on memory.