That's great! That's one of my favorite things about running as well: feeling good and gettin' those endorphins flowing.
It's tough to give any solid training tips without knowing what your running background is like, but here's a few general ones:
- build up your mileage slowly. the rule of thumb I've used is to add around 5% every week, and on every fourth week, cut back about 10%. (these numbers don't need to be followed to a T, but that general progression tends to work pretty well.)
- about half of your runs should be "easy" runs. this could be anywhere from 1-8 miles depending on the person. make sure you keep your pace conversational and you feel good when you're done.
- you should do a "long" run ideally once a week, or once every other week if your mileage is relatively low. again, this will vary a lot by the person, but it should be at least 20% of your weekly mileage.
- 1 or 2 times a week you should try to get a "speed" workout in. this could just be a few minutes of a faster pace in the middle or a run, or 400 meter repetitions on the track, or hills. spice it up and think of fun workouts to keep your runs interesting.
probably most importantly:
- if it ever feels like you're training too hard, pump the brakes and take it easy for a few days. in fact, most of training should feel somewhat easy. it's those couple hard days per week where you want to push it. if every day feels hard, you're going to get injured, and it's always much easier (and more fun) to prevent injury than it is to get rid of it (as it sounds like you already know).
That was more than I was planning on writing, but I hope that that's helpful in some way for you!