Dancing is great exercise, and so is running around after kids.
I think the is discipline. It's east to find an excuse for not doing exercise. Decise which days are going to be your workout days, and stick to them.
Do resistance work, as well as aerobic work. It's important to tone your muscle structure, otherwise you end up looking all soft and flabby.
And do targeted exercise. Work on specific bodyparts. Different bodyparts need different types of work, and respond differently. Also, you may have different objectives. Idon't want to build my arms, just tone them, otherwise you end up looking like Madonna. So that means low resistance, high reps. But I like to build my bum, coz I think a strong butt looks good in jeans, so I do heavy resistance, working to complete exhaustion.
I have a list of exercises for each bodypart - lower leg, thighs, bum, tum, triceps, upper back, etc. At the gym, I do a few miles on the jogger, then I do a split routine where I work some parts on one day, other parts next time I go, etc. Then I go back on the jogger.
Make sure you wear the right kit. The stuff you wear to veg in front of the telly is not the stuff you should wear for exercise, or you will overheat before you achieve much benefit.
Make sure you get the right shoes, or you risk irritating lower leg injuries and aches.
What you eat helps, although I'm not much of a one to talk. I don't eat as well as I should, and I have a lot of take aways, and I maybe drink a bit more that I ought to.
Most importantly, enjoy it. That incredible endorphin high that you ger after exercise is worth every sweaty minute of your workout. It's such a buzz.