I first started by hunting through all the wedding blogs for inspiration. I found tons of ideas but they ranged from the simple to the out of control elaborate. I know my limitations though and decided to stick with the simple MS publisher document. MS publisher has a neat newsletter template and I could change the colors and move things around to my hearts content.
After I had my design the way I wanted it, I brainstormed different content that I wanted to include. I didn't want to update them on everything I had been doing because a) that would fill more than a 4 page newsletter and b) I want there to be some surprises. I picked topics to include in the newsletter that directly affected them.