All the sites you can find over the web represent a company and if you want yours to be as best as you can, you need web application developers that can come up with bespoke solutions. None of the needs you have are the same as the ones others may come up with and this is why you only need to rely on guide lines, rather than rigid solutions.
If you would take the time to visit a web design blog where you can read more on the topic at hand, then you will be sure you can get an idea about how things work and you will also have a few pointers as to what you can ask of the web application developers. All you will need to take into account are the guide lines that will show you the way.
A web design blog is also a very good source that you can use in order to learn from what others have done before you and thus avoid their mistakes. Not all people were born with the best ideas about their sites and if they did not take into account any advice or they did not have any to follow, they might have done things in a less beneficial way.