Really the key is to make people WANT to do it. People don't like to do things they don't want to do. Everyone loves some kind of movement. If you watch them or listen to them for long enough you will identify something that they really want to get better at.
For example, my brother is quite overweight but really likes to play his sunday morning softball league. He plays catcher. It was just using the right diction and rhetoric to get him to start doing explosive ATG air squats and start running sprints in the park. He has been going for 2 months now. Even started timing his runs with a stopwatch.
Once you identify what people WANT to do its really a matter of getting them to add it to their routine. Usually I throw out a small tidbit of how the first 3 weeks are the hardest to add it to the routine ... then after that its natural.
Also, on a physiological note, keep in mind stress levels of the individual. People with high anxiety or stressed out lives are drained at the end of the day. If work is a constant battle exercise can certainly help since it is an "outlet for frustration"... but when we are just starting it seems like a chore and it is REALLY hard for a stressed out, exhausted individual (with catecholamines and glucocorticoids pounding at their brain) to really get motivated to do something as bothersome as exercising. This really drives the point home that it needs to be fun and not "bothersome".
As a small aside...a small part of my blog was actually dedicated to this topic..
Originally Posted by http://www.chrissalvato.com/2009/05/10-common-mistakes-in-acheiving-fitnessperformance-goals/
Let’s be realistic - human beings typically don’t do things they don’t enjoy. Diet and Training are no exception.
This is not to say that you need to love every minute at the gym. When I am going in for my last set of a heavy squat I sometimes can’t help but stare at the ground and mutter, “I really don’t want to do this.” The same goes for the sets of One-Armed Chinup negatives. The negative feelings, however, are far outweighed by the positive, though. All in all, when I walk out of the gym I thoroughly enjoyed myself - despite the fact that I may have had a bad day or didn’t perform as well as I wanted.
Similarly, when it comes to diet, very few of us are happy to watch everyone else eat the birthday cake or huge bowl of ice cream. Forcing yourself to sit on the sidelines of social eating is going to set you up for a poorly balanced diet. This is because many people fall back into the trap of consistently eating poorly after a “day off” from eating well.
This gives rise to two troubling questions: How can I enjoy what I hate? How can I consistently stay away from what I love?
To address the first question, we need to find goals that you would absolutely love to achieve. Maybe you really want to run that mile track around the park. Maybe you play in a weekend softball league and would like to get around the bases faster. Maybe you just saw a video of someone training in parkour and that really lit your fire. Everyone’s life involves movements - find the movements you really enjoy performing and identify workouts and short term goals to achieve them. Going to the gym for years to “look good” will have one of the following results:
(a) You stop working out after a short time.
(b) You become a very boring and jaded person.
To address the second question the answer is simple: don’t. Never in your life should you avoid the things you love. Dieting and training doesn’t need to be boring. If you seriously don’t like tuna and brussell sprouts then you don’t need to eat them despite how they are branded as “healthy.” Instead, identify those foods that are really enjoyable to you AND considered healthy. Make a menu of these healthy foods and then you know exactly what you can eat and what you can avoid. Even then, once you have established a relatively “healthy” way of eating you may want to incorporate a “cheat day” into your routine. The key to healthy living and dieting is consistency. If you have one day a month or week where you eat a terrible meal thats not a travesty. If you have terrible meals every day then its a problem. The best way to stay consistent in eating healthy is to schedule a cheat day 1 day a week (or similar) and stick to it no matter what. This helps keep sanity and you get to really eat the things you love.