Create a new document 850 x 1200 pixels with a white background, double click your background layer, press ok when the box pops up. This has now unlocked your background layer, double click your background layer again and add this layer style.
Select the elliptical tool and draw out a small selection.
Hold the shift key and drag out another selection, over lapping your orginal selection.
You will notice the selections merge togther, reapeat the process untill your have a cloud looking shape like this.
Once you have you cloud shape fill it with the color white, then add these layer styles to it.
Set the layer opacity to about 69%, then duplicate your clouds a couple of times, changing the opacity of each one.
Add your blog title and slogan.
On the text in the header just copy and paste the layer styles from the clouds to the text. Select the rounded rectangle tool and draw out a small navigation size box the side of your blog title and slogan, again copy/paste the layer styles from the clouds to your navigation.
Add your navigation text, using the elliptical tool add some blue dots inbetween each navigation link.
Select the round rectangle tool again and draw out your content boxes like this.
Add these layer styles to your content boxes.
Select the rounded rectangle once again and create a square within your big main content box.
Add these layer styles so it looke like the image above.
Select the square tool and add a dark grey square in the middle. Use the elliptical tool to create a shine effect.
Using the rounded rectangle again add a green rectangle above your polorid, then start adding your content.
Finally select the rectangle tool and create a rectangle at the bottom of your canvas, fill with the color white then copy and paste the layer styles from the cloud, copy elements from the header I.E clouds and title, combine them together to get your footer.
You should end up with something like this.