If you are really tired after exercise, you've probably pushed too hard. The key is to do a little less than you're able and not push yourself to the limit, then add a little bit of exercise each week. That's a big win. Find what you like to do. Schedule your exercise just as you would a business meeting or social activity, then follow through with that commitment.
Plan exercise around distractions.
For parents, it might mean the middle of the day when the kids are in school. For busy executives, exercise might become most consistent when booked first thing in the morning. Find a partner. Ideally, that person should have similar fitness goals. Families might find that picking an activity that everyone can do together will boost the likelihood that they stay active.