I've actually gone from 4:41-high to 4:26-low between my junior and senior year. My freshman and sophmore times were comparable to yours, and my junior times only slightly better. I can barely break 60 for a quarter, even now after 70-mile weeks and college training. The trick was I went from 20 miles per week only running five days to 30-45 miles per week running six days starting the summer after my junior year. Once track started I ran workouts three days per week, or two when we had meets. Did lots of ladders and repeats between 1600m and 200m. Sounds like you have the right idea about working out, so you should just focus on increasing the mileage a little and running faster workouts. Before and after races early in the season that don't matter, run long warm-ups and cool-downs (at least 25-30 minutes). Do at least run a week that's more than 8 miles. Don't dick around on the days before meets that don't matter; get a decent 30 minute run in at least. You have plenty of time to increase your mileage to Peter Snell level in the years ahead -- doing it all at once, or even over one year, will likely get you hurt or impede your performance (IN THE SHORT TERM -- posters who will see me crucified read that). I take it you want to have a good senior year.