One thing to consider when deciding which giveaways you want to enter is how the winners will be selected. Will winners be chosen at random, by judges, by public vote? Does your entry time affect your chances of winning?
Many people use the terms "sweepstakes" and "contests" interchangeably. This is not correct, however. A sweepstakes is a giveaway where the winner is drawn at random. Every entry has an equal chance of being drawn as the winner.
For sweepstakes to enter, see the BIG Daily Sweepstakes List.
On the other hand, contests, also known as skill contests or creative contests, are giveaways where the winner is selected by judges (or sometimes by random vote). They always have an aspect of skill to them. For example, the winner might be the person with the best essay, photograph, or recipe, or the winning entry might be drawn from the pool of all people who perform a specific action, such as correctly answering a trivia contest.
See the Current Creative Contests list for skill contests that you can enter today.
Instant Win Sweepstakes
Instant Win Sweepstakes work a little bit differently. Before the sweepstakes start, winning times are selected at random, with one winning time per prize. The first person who plays the instant win game after that moment is the prize winner. So the winner selection method is not quite random, but not selected by judges, either.