1) If you have girls who you think might be interested but things aren't going anywhere, it can't hurt to ask them. Example: Last week I randomly asked a girl out for Valentine's day. While she said no at first, the next time I saw her she asked me out, and gave me her number (for the second time as I deleted it after the first few months). I texted her the menu of a place I told her I'll be tonight (making reservations and planning to go solo if necessary), and while she said she can't go Sunday she is now texting me, initiating, and acting romantic, and left tonight open (I'm stopping by her work during the day). She is telling me she wants to end things with her boyfriend (who is also my acquaintance so I'm treading lightly).
2) Regarding the girls you just met, or girls you went on previous dates with but who have flaked recently or who are MIA are who went away, etc., don't say a word to them. Use absence in those cases instead, for the whole weekend.
3) Regarding girls you have had sex with and don't want to lose, a maintenance text or gift is in order. They might want to get together on the spot. More girls than you think are single this weekend but don't want to admit it.
4) A great idea is to celebrate Valentine's Day on the 13th. This leaves the official holiday tomorrow open for their official man, it's Saturday which is better, you'll get better dinner service, buffets are running both nights so are fresher, it's not a work night, it's still technically Valentine's day at midnight, and you get first dibs.
5) Regarding gifts, give each prospect you run into this weekend something really small, but enough that they can tell their friends they got a Valentine. Small, organic chocolate bars are best. Or the tiny cards, something hand made, a lollipop or cookie.
6) If all else fails, dress sharp and go out solo both this afternoon (to drop by prospects) and this evening (to check out new venues). It's Saturday and last call for Valentine's Day. Any girls who recently got dumped will be on super rebound and your odds will double just so they have someone. There will be more initial awkwardness followed by unusual eagerness so take more chances.
7) Follow up questions next week can lead to dates. "What did you do last weekend? You were single? How can a beauty like you have been alone on such a special day?"