A well  designed trifold is like a strip  tease,  a  progressive revelation.  The  cover should be intriguing enough to make the viewer keep looking.  The first  opening   should   reveal more  information  but not too much.  Even  when fully open, the  trifold  should  not satiate the viewer, it should still leave them wanting a little more, so that  they  pick  up  the phone and give  that business a call or a personal visit.