The second thing you want to do is do some research - DO NOT try to guess her size - unless you find the couch and dog a more comfortable night than your bed and a nice lady in lingerie. Look into the things she already has and get the size of something similar to what you plan to buy. Women’s sizes vary by manufacturer. Meshes and stretchy materials tend to be more forgiving and range sizes (something marked Small/Medium) are a better bet than something marked Size 4. Bra sizes tend to be true or at least close.
Pay attention to things she comments on when watching movies and such - does she go gaga over the things the girls in Sex and the City wear or does she just HAVE to have that dress Mrs. Cleaver was wearing? Note the colors and styles of her regular lingerie - there is usually a difference between a black lingerie lover and a red lingerie lover. Remember, you want to buy something she will wear for you and something that will cause her to think about you when she wears it - so you want it to be her style.
THINGS TO AVOID AT ALL COSTS!!!!!
Avoid anything marked “Control” or “Slimming” These are to suck in bellies and hide excess weight - not the sexiest message in the world, eh?
Gel filled, water filled and cleavage enhancing bras - Okay if it is her style, but otherwise No No No - she may feel like you wish she were larger on top.
Kinky stuff in general doesn’t generally work as an “I love you” kind of gift unless it is something you two have talked about and decided you wanted to try out. It is not the kind of thing you want to just buy on your own but more of a joint decision.
A word or two about presentation: Handing her the bag from the store with the receipt attached takes some of the romance out of the gift. Most stores will have a gift-wrapping service for a couple of bucks. After all of the thought you put into the lingerie, it is well worth it - otherwise, you can go to any card and gift shop and get a nice gift bag and tissue paper and a sexy card and make your own pretty package.
Shopping online: One of the great things about shopping for lingerie online is that there is a ton of information available that you simply cannot find in a lingerie store. When browsing an online lingerie retailer take a look at their gift ideas, top sellers list et cetera for ideas of what are popular choices.
KEEP THE RECEIPT Even after all of your hard work and dedication she just may prefer something else - always keep the receipt in a safe place and you can go back together to pick out a replacement. Use it as a learning experience to find out what she liked or did not like and next time you can make an even better choice.