A Discussion on Composition

this is an old photo of my art table in it's usual messy state

Recently, I was contacted by a fellow Paper Trader:
"I wanted to ask you some design advice.  Your compositions are always so beautiful and well laid out.  Do you start with a pile of different images in the theme style and just start playing around or do you have a definite image in mind and then go find the pieces to fit?"

I was very honored by her compliment but I found it such a difficult question to answer and my reply was wishy-washy, at best:
"I guess I do both - although nothing is really well thought out.  I almost always start with creating a background I love and then find a central image for my piece...  from there, I will pull together a pile of stuff from my stash that might possibly work with what I've started and I pick and choose several elements, discarding and reorganizing until I find the right combination.  I usually add words last but occasionally I will pick a specific quote or phrase and let it guide my image choice instead.  However, in the case of my recent circus pages, I just printed A TON of images in varying sizes and picked through them, mixing and matching until I had all the layouts I needed - I did it this way because I wanted these pages to have a more jumbled feel and not a overly prominent central image like most of my other work.  I always have a ton of stuff that needs to be put away because this method of pulling out lots of things that end up not getting used isn't very organized!  On the other hand, I usually have a pretty clear picture in my mind of what is in my stash because I'm constantly sorting through it."

So, I'm just wondering... How do YOU design your work?  Do you sketch out an idea first?  Do you find a favorite image and build around it?  Do you just dig through your stash of ephemera until something catches your eye?  We'd love to hear about your creative process!