The major film markets include the American Film Market in Los Angeles (November), the Cannes Film Market (Marche du Film) in France (May), and the European Film Market in Berlin, Germany (February).
Film markets are different than festivals. They consist of sales representatives selling films. By attending, you are getting a sense of what kind of titles are selling that year and who the big sales companies are. It also tells you what actors and directors are in demand. And by getting your face and name out there, people are getting to know you as a filmmaker. And as we know, networking is important.
The film markets do coincide with film festivals so they are easily mistaken for each other. The European Film Market coincides with the Berlin Film Festival, the Marche du Film with the Cannes Film Festival and the American Film Market (AFM) with the American Film Institute (AFI) Fest. However, the markets are about selling films, not featuring and awarding them.
The film markets do hold screenings of the films that are for sale. These are sales screenings intended for distributors. In order to attend, you are usually invited by the sales company or you may try to invite yourself (the sales booths may have extra tickets), and often the initial screenings of a major title are followed by a cocktail reception.
As a new filmmaker, it may be intimidating to visit a market. People are moving fast and they are swamped with sales meetings. If you want to actually sit down with a sales rep, it's nearly impossible to do that without a prior meeting set at least a couple of weeks in advance of the market. You may get lucky if you reach out during the market but unless you have a major project of interest, you will be hard pressed to meet a busy sales rep unless you pre-plan accordingly. Even then it can be tough.
Don't get discouraged. You can always try to meet sales reps after the markets in Los Angeles or New York or via email. A ton of business is done via email. I still have yet to meet a major investor in one of my films. We did everything via the phone and email.
So if you can't pin down a sales rep during a market. Follow up afterward. But be sure to give them time to weed through the post market deals they are wrapping up. They can be just as busy upon their return as when they were at the market -- even busier as they are now back home and dealing with pre-market tasks too.
Bottomline, you should try to attend markets for the experience, the knowledge, and the relationships -- and even the good time (who doesn't want to be in the South of France in May?).