Preparation is key!

It's important to know what type of lingerie your partner prefers. This might require a reconnaissance mission to her underwear drawer and closet. Take note of the types of lingerie she has purchased for herself, as well as their colors and fabrics. This information will give you a good idea of what to focus on when you do your online shopping, as well as what to avoid.

Keep in mind... buying lingerie is not necessarily the best time to be wildly experimental -- it may be better to stick with the tried and true.

"One common mistake men make is buying items that they want to see on their girlfriends or wives instead of what she would feel most comfortable in," says Jezzica Lindkrantz, a stylist with Frederick's of Hollywood. "The big question is: What items would best reflect her personal style?"

It's also important to know what body parts your wife or girlfriend really likes on herself or is self-conscious about. In other words, what areas she would want to emphasize or de-emphasize.

Yet another important detail is size -- particularly bra size, panty size, stocking size (this is usually determined by height and weight, so jot that down, too), pants size, and dress size. This information also can be obtained by studying the clothing in your sweetheart's underwear drawer and closet.

Ready to shop?  Here are a few more helpful tips to make sure your lingerie purchase is a hit...

· Avoid the same old same old. If your wife or girlfriend already has 10 chemises, she might not want another -- it might be time to try a teddy.

· Know just how daring your partner is willing to be. A woman is at her sexiest when she's feeling sexy, so make sure you don't get her something she'll feel uncomfortable or awkward in.

· Remember that sexy lingerie doesn't come in only satin and lace. If your loved one is a cotton kind of girl, a flirty cotton camisole and pajama set will suit her and still be romantic and sexy.

· Lingerie is most flattering when it is sized correctly. Safe items, if you aren't sure, include gowns, chemises, and babydolls—clothing that is generous in fabric and not too tight-fitting. When in doubt, choose items that are one size or that can be customized to fit a wide variety of sizes. When really in doubt, it's better to go smaller than larger. She always can return it if it doesn't fit, and her ego will thank you.

· Well-endowed women like extra support, so if she wears a D cup or larger, make sure you get her lingerie with lots of support in the chest. For example, many types of lingerie have underwire in them.

· Select colors that complement her eyes, hair color, and her skin tone -- if unsure, you can’t go wrong with black.

· Think about what the garments are for -- if it is just for bedroom wear, choose items that you know may be a bit daring, but that you know you will both like.

· Don't settle for something you don't think your sweetheart would like. There are tons of styles and colors of lingerie, so do your homework in advance and have fun shopping!