Men (and women) are busy, but it's important to develop a regular workout routine that you can stick with if you want to see results. Fortunately, it's not hard to design a personalized plan. You can find plenty of ideas online, or work with a personal trainer to create a routine that works for you. No matter what workout routines and plans you follow, keep these principles in mind:
Balance hard days with easy days. Unlike strength training, you can do cardio workouts on consecutive days because cardio workouts don't shred your muscle fibers the way strength training workouts do. But to avoid burnout and possible injury from your cardio work, alternate tougher workout days with easier days. For example, if you go to a power yoga class on Wednesday, make Thursday a day for an easy run and a short strength training circuit, rather than Power Yoga Part II.
The stepwise principle. As you built up the amount of exercise you do, don't pile on tougher workouts each day; follow a stepwise progression that builds up your level of activity gradually, allows your muscles to develop and reduce your risk of an overuse injury. For example, if you are moderately active in a variety of ways, but you want to start running, start with 20 minutes of running every other day for a week. Then, the next week, run for 30 minutes one day, but then back down and run for 20 minutes the next day, then 30. As you get stronger, gradually increase the amount of time, alternating with less time or shorter distance. Don't start out running 5 miles one day, then 8 the next day, then 10 the next day.