Wear nude underwear so it doesn't show through! Don't pre-judge the dress, it's amazing how different they look on - don't have too many pre-conceptions about the 'dream' dress. Take a pair of heels with you. If you find the one, negotiate! Shops will often give money off or throw in a veil, alterations, etc. so play down your budget. Take someone you trust with you to give an honest opinion.
Wear good underwear - they literally stripped me down in the first shop I went into
Agree with other posters - get a friend/mum/assistant to randomly pick out some for you - they look totally different on you than on the hangar
Experiment with material. I was determined to have a big fairy princess like dress with lots of floaty netting. Made me look like a fat christmas fairy. Structured satin was much more flattering on me
Make appointments and stick to them. Dress shop assistants don't mind a bit of unplanned browsing but if you start to make noises about trying a couple on they will go mental as they cannot cope with the pressure. Really they want to give you their undivided attention.
Try the dodgy-looking shops at the end of the high street next to the charity shops. They look naff from the outside but many of my friends have found their beautiful dresses in them.
Schedule in lots of tea and cake stops. It's knackering.
When your mum says "well if YOU like it, then I'm happy" she hates it and it's likely to be the wrong choice. When your mum starts dressing you up like a Barbie in veils, tiaras, shoes, gloves, it's a likely indication she thinks you look amazing and it could be a viable option.
Haggle over prices. We got my dress, veil and tiara from the same shop and they ended up giving us the £150 tiara for free.
I loved every minute of my dress shopping and took 4 months to find mine so most of all, enjoy it, you'll only get to try them all on once (fingers crossed )
Oooh I'm going for my second dress shopping session tomorrow!
Definitely try loads of different styles on. I only wanted lace to begin with, my shortlist of three only contains one lace one now.
Only take people who will behave! My mum didn't.
They'll ask you loads of questions if they're a good shop, stuff like when your wedding is, where, what colour any bridesmaids will be in. They can then help you find dresses that'll suit the venue and time of year and everything else too. Though if you really love a dress ignore all that.
Have you got any ideas yet? Come back and tell us how it went!