I just redesigned our family blog because I finally found a really great tutorial on how to customize your blog to suit your tastes! I even created a blog template that I can whip out and use whenever I want to revamp my blog. If anyone wants to use this template, just let me know. I made sure that when I used any of the 12 x 12 papers that I have on my computer, I resized them not by changing the resolution, but by making them 1450 px wide or by making them 1100 px tall and using two of them for the dark gray area. Then for the light gray area, I just used the eyedropper tool and selected a coordinating color from my background paper and then used the paint bucket tool to fill it in. After that, you can embellish any way you want.
Here's the link to the tutorial. The only thing I had a little bit of trouble with was making sure that my image stayed at 1450 x 1100 px. I can't stress enough the importance of uploading the picture to photobucket using the 1MB upload option that she also stresses in her tutorial. That is the only way that your background image will work and look right. I had tried to use snapfish, but found that using photobucket over snapfish helped because photobucket had a box right by the image that has the url address that you need in the direct link box. Every time I right clicked any image and copied the image address that way, it would shrink my image when I added it to blogger.
I also created my own header in photoshop by making it 700 px wide like she suggested, but I like mine a bit taller, so I set more like at 250 to 300 px tall and 72 ppi for the resolution. I hope this helps any of you who are interested in doing things like this! Before when I tried to customize my blog, I always messed up on the html codes and would get really frustrated by it, often spending way more than an hour on it. Using this tutorial, I was able to redo my blog in under 30 minutes...including the time I spent using photoshop to create it! Easy!