There are few things that make something look good to me like how it is formatted, does it convey the message well, and above all: is it clean and minimalistic? Here are some examples of what I think display these features.
I personally think Apple's website is an over all example of good design. This is because there is plenty of white space, but they continue to give a feeling of order. Parts of the site are located at the top of the page with clear categories. Then a slider with the main news they want the reader to focus on initially, then the minor news.
This is another good example of good design. This is a simple video intro that utilizes simple shapes and sounds to give an "eye popping" experience to put you in a good mood. I personally would have used more vibrant colors though.
This was an "Infographic" project that I made in my Digital Media class that is used to inform the reader about different coding methods for webdesign. I think it conveys good design because it is very simplistic and minimal, yet pleasing to the eye.
This is a common image style that is used to quickly communicate that a company is easily accessible from multiple platforms including computer, tablet, and smartphone. It also means that each platform is dynamic and changes based on the best view for that device/screen.
This is one of those images that is so simple but still conveys 1000 words. It is so peaceful and brings you to a place of vacation.