Its neither screenplay or plot/story. One cannot judge the story or screenplay by looking at the 3mins trailer. For some movies, Story can be judged through trailer, but that's only applicable to intense drama. According to me its a combination of Teaser, Trailer and Songs which becomes the deciding factor for people to watch film on first day or weekend. It also depends on the genre of the film, for an action film Trailer matters more and for a love story Chartbuster songs matters more. For eg. Bhola is generating lot of interest as it has better trailer though a chart buster song will be an added advantag.For Tu Jhooti Main Makkar, its the songs that matters more, the reason it hasn't generated much buzz is due a hit song, if the last released dance number becomes hit,then it can generate huge buzz and giving it a better opening.