I wish I could tell you a specific step-by-step process, but I actually don't work that way when it comes to Inspiration Boards.  Inspiration can come from anywhere, so I often find myself starting the process by feeling inspired by different items.  Once I have the "jump-start" item I develop a color scheme around it and additional items to fill in the gaps. 

I usually just paste the pictures of the items into a word document before I put the board together because I often change out pieces to find just the right look.  Once all of the items feel good, I edit the images, place them on the board, and insert the numeric labels for identification.