Thats pretty easy to do so, look at the following options:

For shorten your individual posts and display like the site you mentioned:

1. Tips from WP codex on customizing the read more.
or
2. Use EverMore plugin, it will automatically shorten all your posts and you dont need to change your posts manually every time with <--more--> quicktags.

For Advertisement management:

You can use this Ad rotator plugin, from simple thoughts this will allow you to rotate your ads from one single text file.

I hope this helps!

Cheers for that SEO notes, Retro Garden is finally coming together

Thanks rhyswynne I am glad this works for you!

Absolutely creating wordpress theme. Me, in my part, i am having hard time doing themes unfortunately i finished none.

to do the images you use custom fields.WordPress Custom Fields: Adding Images To Posts: Using avatar-sized images like DoshDosh.com