@ecommerceprofit as a response to your original question, Google shows the big boys higher in most cases because customers have more brand recognition and better customer experience with those companies. This is not a rule that is always true, but one that Google weighs in an equation.
Seller X that I have no idea how their business runs and their success rate, or Amazon, Best Buy, Target, or Sams Club?
Needless to say, it's not "Why does Google list the big boys ahead of me?" it should be "How do I improve my ranking?"
There's tricks on how to do that. Every month quality data becomes more of the core to Google Shopping's business model. If you include higher quality data than a competitor of equal size who has been listing on Google Shopping for the same time as you, you will on average get more traffic than them.
In four days Google Shopping will start requiring MPNs and Brand or UPCs and Brand for all non-apparel / non-custom made items.
More info: [google.com
If you haven't begun the process of acquiring these identifiers for your products you need to start now, or Google will reject those items from being listed on Google Shopping.
There's other ways to increase traffic as well. One is to optimize your product_type attribute. If you're interested here's the thread where I explain it: [webmasterworld.com
It's the 5th reply down. We've optimized product_type columns and seen increases of over 100% in traffic. While this is not normal it can really give your Google Shopping traffic a boost.
On top of that if you are a soft goods retailer keywords are extremely important. It's all about thinking about how your consumer searches, researching those keywords in your Analytics platform, and prioritizing them in your product titles and descriptions. You can get a huge lift from putting effort into this.