Being that Google Product Search (Base) is free you want to spend some extra time to make sure that you are getting the most out of it. There are several things you can do to optimize your feed.
Content Is King
The Google Base datafeed specs are fairly simple. aside from the required fields there are many optional columns that you can include. Your best bet is to include all that you can. There is a neat tool by Tom The Developer that allows you enter a search term and analyze the data fields that your competition is using. Google loves data, the more data you use, the better your products rank.
Title & Description
The product title and description are the most important parts of your datafeed. You will want to include pertinent info such as Brand Name, Model Number & Product Name in the title column. The description should include all the same information as the title as well as a more thorough description and product details.
Google’s ranking algorithm also takes your feed’s historical performance into account. As long as your account is live, Google collects information such as Click Through Rate and Bounce Rate and analyzes it to see if it is in the consumers best interests to show your product with higher placement.
Google likes to keep it’s content fresh, you should try to upload a feed on a daily or weekly basis for best results.
Google allows merchants who accept Google Checkout to display the Google Checkout logo next to your products in Google Product Search. You can goto your account settings and link the two accounts. This helps your products stick out from the masses.
Google aggregates your merchant reviews from many different rating websites and displays a star ranking of one through five next to your merchant name. Customers have the ability to sort and filter the results by the number of stars a merchant has.
Since Google Product Search is a Price Comparison Shopping Engine, you will want to see that your prices are always competitive for the best performance.