Easiest way: No kids. Two good incomes. Reliably saving 20%. Mid 40s. No college debt or health issues. That should get you to about a million in assets.
kids are an investment...they are your safety net...worse comes to worst, you can rely on them to support you in your late days if things go terribly wrong. its a good way to avoid ending up on the street...you'll always be able to get room and board with your kids. Since our generation won't get any social security or pensions to live off, we are going to need all the help we can get if things go south.
Be nice to your kids, and hopefully they will give you room and board in case of emergency -- but I've tried to help my parents many time only to regret it.