Responsive Web Design will often use several techniques together, regardless of whether it is a Fluid Grid, Flexible Queries and CSS3 Media Images.
The beginning is Fluid Grid Design Grid — a Relative, that is, that do not set the size of the Grid, but the stereotype is defined in relation to other things like the width is font-size% or em units, etc.
The following are Images or defining a Flexible size of Images that are related to the size of the display screen. If the original image is very large. The time displayed in the mobile small screen it should shrink down to a beautiful display, etc.
Finally, the use of CSS3 Media Queries that will allow us to define the style sheets for the various Devices, most of us are writing style sheets, the base from which this group is not based on any of the Devices and then we write the style sheets for Devices that have a screen size, the smallest increase so large that until writing this will help reduce the duplication of code and also to solve simple code later.