I'm half way through the Creating Memorable Characters course and am realising why I could never get past the first few chapters of a book before. I just didn't know my characters enough. I'm obviously not a 'pantser' (one who writes by the seat of her pants) - I have to know my characters well before the plot becomes clear, and I give up if I can't see my way to the end. Going through these exercises is opening up so many avenues for the plot and making richer, more complex characters. Or at least I hope that's what's happening :)
I've also realised that you need to treat the setting almost like a character. I need to really be clear on where they live, work and play - even down to what the house looks like inside and out - before I can add enough detail into the scenes.
I've been using Google images and Google maps a lot to try and get a feel for both the setting and the characters. Visual images spark so many ideas for me. A fellow writer mentioned that she uses collaging to work out plot problems. Definitely something to try - it seems to be how my brain works.