Facebook? Cold approach in the street? Find one in a bar this weekend?
Most Helpful Girl
You can throw a single's party so that you can find a potential match. This takes the couples out of the equation. Get a group of friends to come over for hors d'oeuvres and drinks.
You can also invite people where you work to come over as well. Keep it light by getting people up and talking.
Talk with some people, and get their phone numbers. Pick out one which you made a real connection with. If you really hit it off with someone, you can ask them right then and there to go out for Valentine's Day.
Most Helpful Guy
There's a shop that's opened up with girls available specially for Valentine's day - given the time frame that's best suited lol :D jk 😜
In a bar you may get a tipsy ONS at the most
For most girls that believe in Valentine's day they aren't looking at a quick fix for one particular day.
Unless they seriously consider you a partner, I doubt any girl will be interested in a one day Valentine unless you try your luck on any of the avenues you mentioned above and get lucky. You can also add Omegle & Tinder to your list :)
All I can say is good luck :)0