I would set myself a goal. Sign up for a race in a few month's time, and set yourself a goal, based on your current fitness and how much you want to improve. Then make a training plan to realistically get to that goal. Make sure to ease into it though.

If you have something very specific you're working towards it's a tremendous motivator. There are a few training apps out there you can use. You can also find training schedules on google. If you want to go all out, hire a qualified trainer to set up a training program with you and monitor your progress (the more you invest into running, the easier it'll be to keep yourself accountable).

Another thing that will help a lot, is if you can find a friend to do it with you.  Scheduling runs with someone else makes it so much easier. You can also look for local runs in your area (look on facebook, meetups, ask a local running gear store). They usually will tend to accomodate every pace.

A motivator for me is to run on trails. But I'm lucky to have those to spare in my area.

You can also vary it up once in a while with cross training. You can replace a scheduled run with a bike ride, provided you go twice as long (time-wise) and keep your heart rate up.

If you have to do it alone, maybe you can find a friend or a neighbor that has a dog that could use some running too? I know that's helped some people.

Also remember to keep your goals, and the primary motivators (the reasons you started running) in mind. Monitor your progress, as you continue, you will find yourself going faster/further, and that can be a great motivator.