I'm using Amazon Product Advertising API to handle my full text search. The problem is that the response is taking up to 3-4 seconds (which is about half of my total page load time of 6-8 seconds). Are there any general techniques I could do to improve response time? I'm already receiving the response in compressed format.
Ultimately, I want to be able to display the search engine results page to the user as quickly as possible.
I think you're asking about the concept of Web 2.0. Here is where, in your case, you serve the page immediately and then use an AJAX request that will populate it several seconds later with the content - all the while the user sees a spinning animated GIF waiting for your data payload.
You may want to read further about SOA (Service-oriented architecture) - this just one of dozens of programming paradigm that fit with the whole Web 2.0 theme.