In the 90's I remember how important it was to make sure 90% of your website design was above the fold and laidout for either 640x480 or 800x600 pixel dimensions. Then we moved into the 21st Century and many monitors started becoming 19" and larger which allowed us to edit the dimension size of websites.
Although it isn't as important these days and mostly an afterthought since it has become so commonplace, we still run into some positioning issues. Over the last 5 to 10 years conversion has been a big goal for websites. The goal of course is lead generation and helping the website start and close more sales.
In order to do this your site needs to be nicely designed and also offering solutions that are good for customer usability. I recently talked to a prospect who was in need of an ecommerce solution. They hired a college kid to redesign their site and set up a way to collect payment for a mostly brick and mortar business. Although the site looked nice the shopping cart was weak. The client tried to revamp it and build a shopping cart by themselves. The customer usability was questionable in both revisions and so business is being lost.
The point here is this, even the most advanced web designers sometimes overlook usability basics so of course a novice is going to struggle in this area. So how can you fix this problem? How can you test your site to see if it is set up for the best user experience?
Well there are many high-paid experts that can help you, but there are also other tools. One free tool you might want to check out is one of google's very own tools called Browsersize. Here is a screenshot of Hubspot.com's website. They have done a great job of getting their most important content into areas where the top 80% of browser will see the info without scrolling. They have a few buttons and links that will drive most of the browsers to action and try things or start using their tool.
As I mentioned earlier the ecommerce prospect I was talking about has a site that is hard for a user to understand where to go to buy the products (poor usability). Worse yet, when you get to the shopping cart, maybe a half of an inch of the first product shows up in the 80% range. So if only 20% of people actually see the first product, you can see how this too would effect how much product you are able to sell.
As I reviewed amazon.com, I noticed they had 4 main product selections in the top 80%. This included their search engine so if you didn't see what you were looking for, you could easily search for anything very easily. This is part of the reason they are making millions of dollars consistently.
Best of luck and happy usability testing!