I didn't see JC's comment about getting the tune in your head before I posted-- but I agree completely--not just for singing, either--it is much simpler to work out chords or create an arrangement of any sort if you have the melody clear in your mind before hand.

As to David el Gnomo's thought--it hadn't occurred to me that anyone would think of using the folder/binder while performing, and now that he's mentioned it--if you are still working from the folder, the song isn't ready to perform, and you should keep practicing--