How to have a productive (and great) wedding dress experience (from a married wedding photographer)
1) Bring someone to take photos and videos! Most people bring their mom, friends and/or sister in-laws to dress shopping anyways. And most people want to take pictures. But make sure one of them is assigned that job to get all the shots you want. So you know you have them and can easily access them. You can also ask your dress shop consultant to take photos on your phone - they are always happy to do that.
2) Get photos of the front and back of the dress AND your face in the dress! You do not have to pose for these photos, the key here is to see how you look and feel naturally in the dress. The right dress just makes you happy. When there's something wrong with the dress - if you are uncomfortable with it in anyway - it will show on your face.
3) Bring the shoes you are planning on wearing or ones of similar height. This helps you envision the dress more and help the dress shop consultant accurately assess if you'll need a hem.
4) Get ready for the day. Whatever that looks like for you. Put on make up, do your hair - doesn't have to be all out wedding day make up but you should like how you look. Anything that helps you put your focus on how you feel in your dress and not how you look.
5) Water. Most brides go to 3-5 stores in one weekend. That is more tiring than you think, for you and your bridal party. Make sure you are hydrated and fed. Trying on dresses hungry and thirsty is not fun.
Bonus!
When you have decided on your dress, SHOW YOUR PHOTOGRAPHER! When planning bridal photos it helps a ton to know the look and vibe of the dress. Even the size of the veil can affect the shot list. Also no one loves to hype you up more than your photographer. :)


