There are a number of ways in which a film could be classified as "Oscar bait," and not all Oscar bait movies are the same, but there are some qualities that you can plainly see are tailor-made for film's highest awards. For starters, Oscar bait movies are released in the winter, which is the season where the nominating committee will decide what earns a nomination (so they're fresh in the committee members' minds). With this list of Oscar bait films, you'll find plenty of movies - both good and bad - that are specifically trying to bait the committee and voters into picking them.
What many consider to be the "original" Oscar bait movie, The Deer Hunter, used the Academy Awards as a way to market the movie. They were having a difficult time getting people to watch, but they found that, after getting an award nomination, the average moviegoer was more inclined to come to the movie in a more open frame of mind. This practice has now become standard business practice for films like Shakespeare in Love and Seven Pounds, which had differing levels of success. Of course, some Oscar bait movies utterly fail to bait any Oscars.
So take a look at this list of films that were (probably) made just to win someone an Oscar and upvote the most blatant Academy Awards bait offenders, whether you liked the movie or not.