Give her a card. (Yes, even if she says she doesn't want anything.) This reminds us that you, at least, remembered the day existed. And, please, don't just sign your name. Write a little something special. THIS is our favorite thing.
Plan something. Most girls really don't care how much money you spend. But, people are constantly asking "how did you and ____ celebrate V-Day?" A hike is fun - if there isn't a foot of snow on the ground. Iceskating is good too. A candlelit dinner is nice -- but please refrain from inviting a friend to be your "waiter" and dress in a tuxedo. This is corny and extremely awkward.
Be sincere. Save the Shakespearean poems and pick-up lines for the movies. Tell us how you feel. We REALLY like that.
Remember your mom, grandma, sisters, and girl friends. My dad gave my sister and I a dozen roses EVERY year for Valentine's Day growing up. This really doesn't have to be an awkward "Single's Awareness Day." Even girls, believe it or not, recognize that there are lots of different types of love. :)
And, no matter how big and bad you think you are, WEAR RED AND/OR PINK. I, for one, think it is so cute when guys do this! Be proud.
Make your first date on Valentine's Day. You can do better than this.
Propose on Valentine's Day. *Unless, your girl is begging for it... in which case, we don't care when you propose... just go on and do it already!
Be surprised if you get a REALLY LAME gift from us. There really aren't that many options for what to buy guys for this occassion. Just ask Jeff how many pairs of heart boxers and pj pants he has.
Attend something lame like our local radio station's "Bitter Singles' Mixer." Honestly? Is this really how you want to meet someone? Thinkaboutit.
DON'T suggest anything like this.