Prepare in advance- you know what kinds of things you'll try to say to yourself - so prepare yourself mentally in advance for those excuses.
So when you try to cheat - you know what your response will be (to your own excuses)
Sounds kind of like talking to yourself - but it works
Also - I try to schedule the workout around an event - for example a TV show (my gym has TVs). If I start at the top of the hour - I force my self to watch the whole show - so I'm forced to workout for the full 1/2 hour. Or I'll force myself to listen to a whole CD (about 45 minutes).
Yet another great thing is to take classes (aerobics, boxing or whatever suits your taste) - Once you get in - it's very difficult to leave early - you feel obligated to do the whole class - and you will get a great workout.

Sometimes I'm going to do 30 minutes on the elliptical and at about the 20 minute mark I start wanting to quit. At that point I start thinking to myself how I'm not going to feel good if I quit early or that I've already gone more than 1/2 way and if I can go that far, I can definitely finish. Just think about the calories you are burning and how its going to help you get to your goal. Good luck!

i've been noticing that once I get myself to the gym, I find myself rationalizing why I should cut my cardio 5 minutes short or not do that 2nd set of weights. Any great ideas to get myself doing the opposite?

Hi Spring~ I talk myself in and out of actually doing my regular amount of time while working out all of the time. I also talk myself in and out of adding more time on. I use my workouts as motivators to talk myself out of cheating and continue on track as well. I guess the best thing that works for me is to set my workout goals before hand and push myself to stick to them. It is such a huge sense of acomplishment when i meet my goals and then I really try hard to hang on to that feeling. Not sure if that helps or not.....................

Thank you all so much for your input! It helps a lot. I was so tired to day but managed to get out and exercise. I even talked myself into working out more instead of less!!

I find it helps me to put little notes all over the house and on mirrors and things like that so that when I walk by i see that and then I get motivated to do it instead of making excuses.... I also have pictures of things that i want to fit into..... always helps me get back on track... might help you also...

Spring, I don't know if you love music. What has helped me a lot is my iPod. I have a playlist I call GYM. I have a lot of upbeat music on the GYM playlist. I highly recommend an MP3 player if you don't have one already. It has helped me tremendously. Good luck and remember, the more you keep making exercise a top priority in your life, the more you will feel a NEED for it, instead of feeling that exercise is a grueling chore.