kawamake different routes around your town/city for a change of scenery
This is the biggest thing for me. Variety makes you pay attention to your surroundings and keeps you from becoming bored with your run. I highly recommend traveling to a park at least once a week if you only have road running available to you.
I also recommend running for time rather than distance and never doing a run that requires laps. It is significantly easier to justify in your mind that once you get halfway every step forward is closer to finishing than to have to do another lap when you are already feeling done with the run.
An even better solution would be to join your local running club or find a friend that wants to run with you.