A header of the blog or a site is a first impression on the visitor. Here’s a website called “freewebpageheaders” which provides header images for blogs and sites for free. Free Webpage Header Images They serve a huge library of header images according to various categories.
It’s possible to add favicon to your blog as many top-websites have such as Google have “G”, MSN have their butterfly and blogger have a “B” by default. Not actually a trick but a website called myfavatar hosts favicons of blogs and sites for free.
Ads should be placed where people see them. To follow this principle and have more exposure and more number of clicks, it is recommended to have Adsense ad shown just below the Post title or at the beginning of Post content.