Q: What do you do when you don't know how the next part of a song should go?
A: clear your mind, and do accurate, timed run throughs! i usually do it with a click. and if i really get stuck, i do a 'door touch' to try to re-set my mind. i walk over to the door and touch the door knob and walk back to my seat and then play the song, all the way through. the more you can re-set your mind, the more accurate picture you will have of the song after doing a full run through. after doing an accurate timed run through, you will start to get a vision of an answer somewhere within the last few seconds of the known song, and it may linger within the first few seconds after you stop. it will start to fade after that. the whole secret is to pay very very close attention in this moment, and try to gather as much info as possible about the situation, (of course you might get lucky and lightening might strike and you might find the whole solution instantly) but try to play process of elimination -- sometimes you might find out you 'definitely don't want another chorus' or you 'definitely want something with the same chords' or you 'definitely want something different' or you 'definitely want something the same' .... try to listen to as many clues as you can find, to narrow it down, ... and then clear your mind and do another run through. don't forget that if you already have 'critical mass' in the song, you are never obligated to do anything more, the only thing you are obligated to do is 'carry the song home', which might even mean ending it sooner than you thought. or it might mean repeating what you have. or it might mean doing something totally different. it's important to stay very open, and again, the only thing that will really produce a reliable solution is clearing your mind, and an accurate, timed run through, and paying very close attention to the moment when you reach the end of the known material. i hope that helps