One of my top pieces of financial advice is 'marry well'. Marry as a verb, present tense not past. I don't mean land yourself a Mr. Darcy, although that doesn't hurt. I mean the act of being married, and how you approach marriage as a couple.
If you choose a spouse that is frugal, rather than spendthrift, it makes a difference.
A spouse that supports you - pushes you to grow and develop. In my case, my wonderful wife comes from a culture that negotiation and haggling are more acceptable and the norm, and she's pushed me to learn this. A little negotiation when asking for a raise, or starting a new job, or buying a car, goes a long way.
Being married (I'll count common law in here) has tremendous benefits from an economic perspective. Shared accommodations. Medical benefits. Travel and vacation costs as a couple are cheaper than two times one. The value and benefits are numerous - this is why legalizing gay marriage is an economic imperative and not just a moral one.
Being married and having the support of a spouse as you make significant life changes is also critically important. Changing jobs, careers, having kids, moving across the country - these are all things that are stressful and challenging but easier when you have the support of a loving spouse.
Getting on the same page financially is key in any marriage. The most common cause of divorce is financial strain. Understanding and agreeing on your financial goals as a couple, goes a long way to addressing strife.
Investing in the marriage is important as well. When you have kids, taking one on one time, date nights, etc - a hell of a lot cheaper than divorce.
And although divorce is expensive, I'm pretty sure if you did the math on financial outcomes for married couples who separated after 20 years vs. single individuals they'd come out ahead, despite the challenge and change in situation.
Most millionaires in North America are not high flying CEOs living in posh mansions, but quietly happy married couples who've been together for 30 years living in the burbs.
So, my advice is this - marry well. Take time together, talk about your finances, agree on your goals, find ways to celebrate your successes.