Adding a new feed is easy.
Copy the URL of your favorite blog. Your blog must have an RSS or Atom feed associated with it, but nearly all blogs do. The address of the feed associated with that blog is usually more than just the blog's address, but that doesn't matter. Google will find the feed associated with that page for you.
When you're logged into your Google Reader home page, you can add a feed by clicking on Add Subscription.
The button will expand to reveal an entry box. Paste the URL of your blog into the entry box. Google will then add that feed to Google Reader for you.
Browse for Feeds
If you don't know the address of your favorite feed, you can still find it by browsing. Instead of clicking on Add Subscription, click on the Browse next to it.
Type in keywords in the Search and Browse box on the lower middle of your browser window. You can see a list of feeds and how many people are subscribing to each feed in Google Reader.
Add BundlesYou can also add preset bundles of feeds by browsing. Popular feeds are bundled together in topics, such as News or Fun. It's an easy way to add content to your reader.
Simply click on the Subscribe button to add the bundle of feeds in its own labeled folder.
Add by Username
Do you have friends with a blog on MySpace or photos on Flickr? You can add your friends by their username. You can add feeds by username for several popular social networking and blog sites, such as MySpace, LiveJournal, Flickr, and Xanga.
Click on the Browse link and then Enter your friend's username in the username box. This is just under the Stay close to friends and family! label. Next, select the appropriate blog or social networking service from the drop-down box on the right.
Note: Google Reader will only read the public entries from your friends. You still have to go to the Web site and log in to read their private entries.