1. Be versatile. Have several types of exercises that you that you enjoy and always keep a lookout for more. Perferably, they should not all emphasize the same muscle groups. Injuries are generally unavoidable in the long run, so if you love to run and injure your ankle, you can still swim, for example. It also helps to have a varied exercise portfolio to keep it interesting. There may be a "base" sport that you excel at and love beyond all others, but that is also the one in which you are most likely to have an injury. So diversify; you'll thank yourself.
2. Keep it simple. At the end of the day, it is about calories in versus calories out. So, technique means something, but certainly not more than just doing it. An hour on the eliptical machine at a lower setting, is better than missing two days because you overdid it. Moving your body, even if not at your peak or optimal potential, is better than sitting on the couch, depressed or injured wishing you were back at it. Technical exercise is always superior to just exercising, but doing something every day is far better than planning and waiting for something perfect. Concentrate on style and technique as you strenghten in body, mind and in your exercise routine. In the beginning, settle for something less than perfect, in favor of enjoying it and actually showing up to do it. Improvement will follow as you begin reaching your goal. Injuries will be far less likely as you gain in fitness and confidence. Nothing is a substitute for enjoying what you do. So keep it simple, stupid.
3. Be determined. There are a million reasons not to work out and you can't listen to any of them. They come at you when you first wake up in the morning and they continue pestering you all day, even during your workout and then they will keep it up until the next time you go. Just don't listen to them. One thing that really does help is to do your exercise first thing in the day. This really takes determination. In the summer you feel like goofing off. In the winter, it's dark and cold. So be determined to be determined.
4. Be patient. Remember the exercise sage's saying, "This dome was not built in a day" when patting your out-of-shapeness or viewing yourself in the mirror. You didn't get into this situation over a weekend, and you will not get out of it in a weekend. Weigh yourself without fear and do it frequently and always keep the faith in the math of exercise: if you reduce the calories and increase the exercise good things will happen. They really will.
5. Be vigilant. When exercising, always listen to what your body is telling you. If you are trying something new, like a "free weights day," instead of your usual all-cardio workout, do a little less weight on day one than you might think you can. Give your body a break with an easier entry into new things. Exercise is not punishment for bad behavior, it is a reward for living right. What you used to be able to do is far less important than keeping a positive attitude about your new regime. Explore each new addition to your workout as if it were a new friend joining your inner circle. Take it slow. Take it smart. Be vigilant.
6. Be temperate. Eat as little as you possibly can. Most exercise/diet programs to lose weight should begin with a drastic reduction in food intake. Go to six small meals a day. Keep each meal to 1/6th of your target calories. For example if you are limiting yourself to 1800 calories per day, eat six 300-calorie meals. You will automatically learn portion control. This is a lot easier to learn when each serving is only about three hours apart. Use a small salad plate for all of your meals. At first this may seem sad to you ... such a little plate. But, in time, you will love that little plate more than even the food that is on it. After a while, a big 13-inch dinner plate will seem disgusting to you and you will long for your little plate back again. Exercise volume will grow as you get smaller. It is much easier to do 100 abdominal exercises after losing ten pounds than it was in the beginning. Just as you will find clothes fitting than haven't fit for years, you will also find you can do things far easier than before. Temperance in eating is central to exercise. You will also find that each meal suddenly has better food in it than before and your chosen calories will be chosen far more carefully and intelligently. For most of us moderation is not really attractive, so be temperate and enjoy quality eating with your exercise.
7. Be yourself. This may seem paradoxical to you at first, but in time you will see that the only diet and exercise routine that will ever work for you is the one you really like. When someone offers you a dessert, eat a sliver instead of a slice and deduct the calories from the next meal in your six-meal routine. Take it as an opportunity to resolve to definitely not miss your next workout. In other words, use your head to reenforce your program even with the occasional sweet or other caloric deviation. Your program is a tool to use. Build the most important ingredient into your program ... you. Self-denial is always part of losing weight and gaining fitness, that's for sure. But you can also be reasonable and affirmative about not always just saying no. There are better answers to the challenges of losing weight and gaining fitness than just a big fat "no." As you find them, through experimentation and, yes, patience, you will "be yourself" in new and wonderful ways.
8. Keep some sort of record. It could be just a date and weight record. It could be an exhaustive record of everything you eat and everything you do. It depends on you. But definitely keep a record of what is the most important thing to you. It might be just the days you did exercise. Anything. But believe me, that record will become very precious to you as the results come slowly in. Success is a very personal thing, so perhaps the record is a confidential one. But keep a record from the beginning and you will love it. If you already started your program and didn't keep a record, start one now.
9. Be forgiving. No one is perfect. Be not afraid to start over. Starting over is a key to reaching success. Be endlessly willing to do it, but learn to build a resistance to the setbacks that require it. Remember, this is a process and a learning experience. As you walk towards your goal you may stumble. Relish those moments as opportunities to prove your determination and resilence. If only people knew how close they were to success just before they gave up. So be forgiving and never give up.
10. Be happy. Just look around. There are people all around you who have given up. There are people all around you who have never even started. There are plenty of people all around to inspire you. Every day is an adventure in moving towards your goals. In time you will see that your goal was never really to lose weight. You will see that your goal was never really to be in great physical shape. Your goal was always to be happy. So even as you begin, especially as you begin to succeed; then as you succeed beyond your wildest dreams; and when you realize all of your short term goals are behind you ... then you will finally see the goal of all goals: to be happy. You will realize that this great goal was always within your grasp at every point. You can wait through all the trials and tribulations ahead of you to discover this truth, or you can take my word for it right now. Be happy. It makes everything else to come much, much easier.