Film markets such as AFM, Berlin and Cannes help you sell your short films. To get the max out of these festivals, plan screenings, and get people excited about your movie. Market your screenings online, and get people to know about the film.
DON T show your film on youtube or upload it to any video-sharing network. This automatically disqualifies you from TV distribution. Screenings should be kept private if on your computer, played at festivals on the big screen or on DVD for distributors to look at. (A trailer can be uploaded instead for video sharing websites)
Send your film out to distributors. Call them up, tell them about your movie. Has it played at festivals? Why should they see it? Develop a pitch, and make them adore you.
Do you want one distributor to take care of worldwide rights or do you want to send it to several? Be careful when signing any document. Always get a second opinion.
Best of luck!