I realize this question may be too general to answer but even some basic direction might be helpful for those of us with less experience in ths area. And besides, this topic gets much less attention than orchestration.
Here's my situation:
I've been working on a motif based piece that I want to have a 'grand', 'opening credits' kind of sound. I've arrived at a melody line that I'm satified with but I'm having a tough time finding the right 'sound' harmonically. My background is in writing pop and some jazz and needless to say these approaches aren't giving me what I want to hear. Sorry I can't be more specific (if I could I probably wouldn't need to ask).
Here's a link to a pdf leadsheet of what I've got so far:
Thanks to falcon1 for hosting it.