If you have a large social circle, the easiest way is to ask a couple of your friends to hook you up with someone who is single and looking for a date on Valentine's Day. However, keep one thing in mind - there is no such thing as an easy ride. Only because your friend knows a girl or a guy does not mean you take the date for granted.
If your friend does introduce you to someone, be sure to appreciate the effort. You need to civil and realize that the other person also made the effort to try and get to know you. Don't come across as desperate for a date and strike up a normal conversation.
Once you start getting along with the person, you can talk about likes and dislikes and get to know him/her better. The point here is to make sure you don't rush into something just because you want a date for Valentine's Day.
If you see things are going your way, you can talk about the other person's plans for Valentine's Day and share yours. If the two of you think alike, or want something similar, you can politely ask him/her to consider spending the day with you.
If the other person agrees, you have a date. Now it is up to you to plan a memorable date if you really wish to take it somewhere.