[header] How to run a fast half mile [title] Build endurance. [step] Before you build speed, you need to build the endurance that will let you run the full half mile. Add sprinting into your regular running regimen to start building endurance. 
[substeps] Start with smaller distances, such as 100-meters, and work your way up. You might also start at 200 or 400 meters, depending on your experience.