Pick a spot to run at that is approximately 1/2 mile to 1-mile distance. It could be at a park, school, or track, somewhere you do not have to worry about traffic or dogs. Take the first lap slow for a warm-up and time it. Do about 5 to 7 minutes of stretches.
Start your run and time each lap to see what you splits are. Improving your negative split time can be accomplished by training with negative splits. Run each lap faster than the first one and so on. Always start out slow with an easy run and as each lap come around focus on form and lifting your knees. Even if you only ran one second faster then the previous lap, that is a negative split.