A grid can be the skeleton of your website. They consist of invisible lines that make the page square and lined up. The main purpose of a grid is to create a set of guidelines for how elements should be placed within a layout.
Advantages: makes the page uniform, gives it more structure
Disadvantages: might restrict creativity, hard to learn how to use
Rule of Thirds
Many designers use it to divide their layout into three sections vertically and horizontally. The rule of thirds is an easy way to apply proportion as we make decisions about layout.
960 Grid System
The 960 Grid system is a CSS framework, which is a system to handle the structure of a website. The 960x is the most common grid system, because it has many factors, which provides a lot of flexibility for the width of columns.
There are three layout foundations:
- 12- columns
- 16-columns
- 24-columns
These templates help you arrange the container, logo, navigation, content, footer and whitespace. If you’re unhappy with the looks of the layout, it could easily be fixed by moving around elements and resizing them on the grid.
Grid theory and anatomy 