As technology makes design easier every day, a lot of people tend to get away from the basic principles that make the web design work. These elements of design are important to understand to create an effective design. Trends in design change all the time, but these fundamentals have been unchanging and will likely never change, so they are important to note and remember.
A great design has good balance and proportion of the design elements. It also has contrasting elements, either in size or color, within it. There is a clear focus that establishes the point of interest for the viewer and their attention, but directional forces are also used to direct viewers to where their eyes should be looking. Repetition and rhythm can also be used as directional forces and provide a continuity. Variety is important, but there must be some sort of unity among that variety to give it an appearance of oneness.
While trends continue to change, these basic elements of design are often forgotten. These principles should be considered and followed no matter what kind of trendy design work you are embarking on.