I've had several Website Design clients ask me why many sites look similar in design and look and feel. Some of this is like complaining, "My boyfriend looks too much like Brad Pitt". A good-looking site is not a bad thing to have, even if someone else has a similar good-looking site.
The reason why you see so many sites looking somewhat similar is because of three converging trends in web design.
The first is what's called "flat" design, which was introduced with Windows 8. Previously most web designers would create images for many elements where buttons would have a three-dimensional look, and usually had shadows and other lighting effects. Today that's considered somewhat old-school, and we use CSS3 and HTML5 to create interactive buttons and page elements without requiring images.
RESPONSIVE WEB DESIGN
The second trend is the use of "responsive" website design. A responsive site automatically changes its formatting depending upon the device on which it is viewed. So you can use the same website design on your computer, your tablet, or your phone. Most of these "responsive" websites are based upon a framework called Bootstrap, which was originally developed by Twitter for use on their site. So, for example, on my site if you squeeze your browser window down to the size of a cell phone you will notice that the menu becomes a drop-down, that elements that are beside each other on your computer will rearrange themselves on the page to be under each other. Almost all the copy will be easily visible and usable on your cell phone.
HTML5 & CSS3
The third reason is the introduction of HTML 5 and CSS 3, which are new coding protocols that give us a great deal of flexibility and functionality. Today we can do things with the website that would have taken a desktop application to do in the past. By using code elements, rather than images, for buttons and headers, we help pages load faster, since we don't have to download those images.
But if you are more comfortable with a more conventional, old school design, I can still use Bootstrap, HTML 5 and CSS 3 and make the site look very similar any website design that you show me. You will get the look that you like, but with all the advantages of the latest website design tools.