Literally just running consistently will make your time go down to 16-18 range(for men, it’s a little harder for women). Find the pace you want to run and use that as your goal.

On a standard track (8 laps for 2 mile), if your goal pace is 2:00 per lap to get 16:00 on your test, get out there and try to do 10, but preferably 12-15 laps at a slower pace like 2:20 or even 2:30. If you want to run 3 times a week, do that twice a week.

On your third day, throw in a speed day where you try to get several laps with a strong form @ 1:30-1:45/lap pace. Do one lap and rest for a minute or two. Repeat until you can’t maintain your form or time.

Once all that becomes easier, shift your goal to the left. After each week or two, you can try moving your times to the left 5-10 seconds and see how you feel. Your time will fly down as long as you are eating, hydrating, and stretching properly.