You should begin with more volume, less intensity. This might involve jogging a couple of miles a few days a week and perhaps some 400s or 600s at the track (2-3 mins rest). As the weeks go on you can start tapering those track workouts down to shorter, faster intervals with more rest. But this should be done gradually. If you try to go too fast before you're ready, you're just begging for an injury.
During this time you should also be hitting the weight room, doing some core strengthening, and possibly plyometrics. Doing strength training at the gym is going to make you a more durable sprinter and prevent injury. Doing core strengthening (abdominal exercises) will help you with form, energy transfer, etc. Core strengthening is extremely important. Plyometrics such as box jumps, bounding strides, etc will help you become more explosive. But some believe that sprinting is the best plyometric exercise if you are a sprinter. It's up to you.
In college our coach would often have us do an early season workout that consisted of 10x100m in 13-14 sec (maybe, I can't remember the times) and in between each 100 we would do 30 seconds of some kind of abdominal exercise (scissors, crunches, bicycle, medicine ball catch, etc). This workout was usually done on the infield. Of course, we weren't running those 100s all out. The purpose of the workout was not to develop explosive speed. It was early season conditioning, preparing us for the intense work we would be doing later on.