Pinterest can be a good place to start, but try to go for the "big picture", rather than just overly stylized, extreme closeups of eyes. Those are great "paint by numbers" tutorials, but you need to remember that these are painstakingly lit in a certain way and may look very contrived in real life. Photos from the Red Carpet are often a much more realistic indication of how makeup will actually look in broad daylight. If there is a celebrity you admire who shares your coloring, Google images of her at awards shows to see certain looks she has done. These shots are usually not as heavily photo-shopped as magazine ads and covers and will manage expectations better.
I like to use colors from the wedding as inspiration. If your bouquet has lots of pinks, a coral lip will look "off". If your maids are in lilac, you may want to pull a bit of that into your eyes or lips. This helps everything flow.
It is a good idea to share with your artist whether you want your girls' makeups to somewhat "match". A cohesive style can really pop in your photos, IF you can get all your girls on board. You know their makeup style; if they all love darker eyes, they will feel downright naked in a minimalist look. Conversely, if they are all makeup shy, they will be miserable in bright red lips! Recently I did a wedding where the girls wore charcoal and the bride wanted their lips to be bright sheer pops of red, coral, pink. Unfortunately, not all the girls felt comfortable and asked for that to be changed, even though they looked like movie stars. That put an end to the "cohesive thread" the bride was going for. I had another wedding where all the girls did exactly the same sheer tomato red (it was a patriotic themed wedding) and it looked incredible. The girls were all thrilled that it looked great on everyone.
The more prepared you can be, and the more upfront you are with your maids, the happier everyone will be on the day of the wedding!