Well, I know I spent my summer running everyday! Took a while to.
I first started only being able to jog 2 laps before almost calapsing (if that's how it's spelt) and now i'm on 8 laps 3.6 Km / 2 miles. And to challenge myself, I start a light jog, by the end of the run I phase out of RUNS and SPRINTS for 5 laps. Always... ALWAYS... Try to excel in it as well. Try to beat your old running distance. Even if you're body tells you to stop... Slow down, keep running and or jogging at a steady pace. Don't stop until your training time is up and or over. The longer you run aswell you're giving your lungs a steady workout. And by atleast the end of the year, you should be able to run 8+ laps around a track field and or soccer field.
That's my experience anywho.
... EDIT: spelling correction