Signing up for AdSense:
To sign up for your Free Google Adsense Account go to
www.google.com/adsense
Google require you to have a website or a blog before you can sign up for an
Adsense account so if you do not have an account, then create a blog at
www.blogger.com (free). When you created your blog, use your blog URL
when you sign up for an AdSense account.
Once you get your account. You can log in to get your ad code which you put
on your webpages to show AdSense ads. There are different style of ads you
can choose from. You can even change the colours around.
Ad Placement:
According to the research done by The Eyetrack III research released by The
Poynter Institute. A visitor first looks at the logo, then looks for the headline in
the top LEFT of the screen and then scans down the left of the screen for site
navigation before looking around the page.
Here are some snippets from the research site:
"The eyes most often fixated first in the upper left of the page, then
hovered in that area before going left to right. Only after perusing the
top portion of the page for some time did their eyes explore further
down the page."
"Dominant headlines most often draw the eye first upon entering the
page -- especially when they are in the upper left"
"We found that ads in the top and left portions of a homepage received
the most eye fixations." (this is where the Google Adsense ads shouldbe)

What we need to do is make sure we place AdSense ads near the top of the
page and some on the left of the page. This strategy is proven to get you
more clicks which result in more money for you.
This is also a sneaky way of making the ads appear as navigation links.
Visitors click without realising they’re ads. This can be extremely effective
indeed.
You should also create the ads so they compliment your website’s colour
theme and style. They should fit right in and look natural. You can change the
background colour and text colour of your ads from you AdSense account.
Another AdSense feature you should add to your site is, AdSense for Search.
This is like an ordinary Google search box but instead of displaying just the
ordinary search results, it displays AdSense ads on top of the normal search
results. With this you can make money whenever someone searches from
your site and clicks on the results!