I brainstormed ideas by going on Polyvore and picking items that I would use in my room. I also chose items that I would replace things in my room with. For example, I own a desk, but picked out another that would match and work better.
Consider uploading photos of cool places and spaces that inspire you. Upload scans of hand sketches showing your first ideas.
Brainstorming ideas is the step where you gather inspiring images of buildings, spaces, colors, materials, furniture, etc. Learn more in this video.