Good feed = quality data/complete data and well optimized. Use UPCs when you have them, use custom attributes when you can.
optimizing the feed is simple you just have to put make model and condition if you have mobile product you could use nokia n73 black sim free unlocked... make it searchable by user
i have one shopping site and i want to display my product feeds in shopping site please help me for it and tell me what is actual process of product feeds submission.
Might want to consider having a custom page setup that outputs your products directly to an xml file used for entry into google feeds. That way you sync your products on your site with products being sent to the google product feed.
for google product feed check this url : http://base.google.com/support/bin/answer.py?hl=en&answer=59462#option1
Fallow Google base specification and make product feed where you can give field & data (Fields :- S.no, URL, Product name, Category, Description, weight, image URL and related data ) etc.after that making excel sheet and convert excel sheet into text delimited file . After that upload datafeed with Google account.after 24 hours , your data feed would be verified then check your status on google merchant center.
Use keyword rich descriptions and attributes. I believe having good reviews (which are aggregated from other shopping comparison sites) and low prices also have an effect on the algorithm used to rank your products.