How do I optimise my Google Base feed?

The first and most important area to cover is having a good quality data feed. Gathering some customer reviews can provide users with trust in the seller and can also encourage sales.
http://base.google.com/support/bin/answer.py?hlrm=en-in&answer=25161
This link provides examples to improve your data quality, the best thing you can do is include relevant data in appropriate attributes.
http://base.google.com/support/bin/answer.py?hl=en&answer=78170
If that fails [...]