All events are social in nature, and you want to stack the odds in your favor if you are new and/or don't know too many people.
Location, Location, Location
If you aren't getting the dances you want, one of the bigger factors is location. All rooms have "sweet spots" for being asked, usually places where more people enter and exit the dance floor. Your job is to look around the room, find the sweet spots, then get your glammed-up self standing in that area.
If you realize another spot looks better, move. If you are not getting dances in one area, go use the restroom and start over in another area. Move, circulate and smile if you skip more than a couple songs. Few things are worse for your social assimilation than sitting for half a dozen songs between dances, so be bolder and move the second you realize your current location isn't the best.
Minimize the Barriers Between You and the Dance Floor
Don't make it difficult for someone to get to you. If you are female, are you easy to ask if I'm just entering the room? If the music started, do I have to navigate around four tables and the kissing couple to ask you? Move if there are too many tables, chairs, people between you and the floor.
Stand When Practical
Are you sitting or standing? As a rule, standing close to the edge of the floor dramatically increases your odds of being asked. My concept of "when practical" means when you are not dancing and you want to dance as soon as possible. Sitting doesn't take you out of the game, but it reduces your odds.
If you are in the back of the room, or sitting off in a corner, most people wonder if you want a break, and unless they know you they are less likely to ask you, especially if there many other choices. Make yourself easy to be asked.
Last May, I wrote an article targeting ladies going to clubs and not getting enough dances, and the same principles apply at any new event or congress. Check out "Why Don't the Guys Ask Me?" for some additional tips and more details. While it's written with the ladies in mind, guys may find some interesting things to think about.
Nothing will ever be attempted if all possible objections must be first overcome.