I'm a 17 year old male who is just graduating high school and wanted some tips on how to improve my running speed. I used to do track non-competitively back in 7th grade and remember having a 7:50 mile and 3:30 800m, but haven't pursued it since then. Today, I ran an 83.4 s 400m, after not running much for a while, and want to get in shape before college. What would be a reasonable goal for me by the middle of September if I run regularly on a daily basis on the 400m and 800 m? I'm not too interested in improving my mile or longer races, but if I could improve on those that would be helpful too.
Also, how exactly should I train? Should I do 400m laps and rest for a minute in between, or should I try running full on miles? I'm totally lost on what to do, but I just want to get shape before college.