There's no secret formula ... you just have to pull your shoes on and get out there.
But you've got a good past record, haven't you. The sort of interval training (run/walk/run/walk) that you were doing before is ideal.
6 miles was quite a long way. Some people's target for the year is to "do a 10km" ... and you were doing about that several times a week. Good you ... !
Make sure you have some good music on you iPod, if you have one. Keep a separate Playlist of "jogging tracks".
And ... if you can stretch to buying yourself a little treat ...
I've got a Garmin Forerunner 205. It's one of those GPS things for runners. It's a great motivator, because you can see how far you've run, what your pace has been like, etc, and then you can download the results on to your computer, and see yourself improving.
Like all technology, they started off being really expensive, and now you can get a Garmin 205 on Amazon for about £80. I know that's a bit of an outlay, but I love mine. And it shows on the printout if you've been lazy, and not been out for a while (but no cheating, and taking your GPS out in the car with you, LOL).
And hey ... look at the weather ... this is the best time of year to get back into it ...
You have the summer ahead of you !!
Go do it ... !!!!!!!
J x x x