Keep your treadmill at a 1% incline or higher. Running on a treadmill is less impact than running outside on any surface. So keeping the incline at 1% or higher will help to bridge the gap between road racing and treadmill training.
Cover up the display flashing all your stats in your face. If you're staring a clock in the face, time crawls...and having a clock tick, tick, tick by makes a run feel long and arduous - not fun. Just peek at the display when you want an update, or if you're trying to run intervals.
Don't get into the numbers trap. What I mean by that is, when you start training, walking at a 3.5mph might feel tough. But, as your fitness improves if you stick to a 3.5mph walk you're fitness will plateau. I can walk comfortably at a 4.4mph, and up to a 4.8mph before I start to jog - don't be afraid to up the speed. If you're number sensitive, simply keep the display covered while you up the speed a little bit at a time. Once you hit a speed that challenges you uncover the display and take a look. My guess is you'll be going faster than you thought possible.
Find a show that pumps you up. Think of a movie or tv series that has you off the couch and grooving, and that's the show (if you have a tv infront of your treadmill) you should plug in and run to. My personal favorite is Glee - seriously people, give it a go. The music is serious motivation!
Play games. I play the "run as fast as you can until ______" game. Just fill in the blank with a number or point in your music or show. Try to avoid filling that blank with something physical like,"you're tired" as that comes a lot quicker if you're constantly monitoring yourself for it.
Work out with a friend. Are you at the gym? Get a buddy to jump on the treadmill beside you, go for a jog, or race it out! Running with friends can be the extra push you need to get going.
Hydrate. Sometime water is forgotten when the sun isn't blazing down on us, but when you're on the treadmill you still need water. Utilize those cup holders!
Do you have some tried and tested treadmill tips? Or do you have any questions on how best to approach this type of training? I'd love to hear your thoughts!