Your training should be set up so that you can have your best performances in the meets that are most important to you. This is why you should schedule backward from the most important events. I schedule back in 12-week blocks from my most important meet to the start of my fall. I usually set it up in 3 weeks on followed by 1-week light format. So basically, it's 3, 12-week mesocycles with a week or two in between each. This way I can begin to taper with three weeks towards the end with one peak week during my championship week. I just decrease the volume, and density of whatever we are doing at that time and put particular emphasis on quality and execution, and no big runs or jumps with less than 10 days out from the target meet.
At the beginning of preparation, training will be more pronounced using the shortest distance that makes it easier to keep the velocity higher, with the passing of each the cycles, using the three distances in almost similar proportions at first and then for 200meter, even with the prevalence of longer distances (80-100 meters).