I'm about to give you the keys to the kingdom.
There are certain cornerstone actions, routines and habits that, once in place, ripple out and have a positive effect in all areas of your life. Combined, they each reinforce each other, combining to have a huge impact on the quality of your life, and what you can accomplish.
I call them Force Multipliers.
Being healthy and strong is great. In fact, being strong is one of the key ways to slow the ageing process. For that alone, you should exercise regularly. But you'll also think more clearly. You'll be less likely to suffer from things like depression. You have more energy and can be more productive. And you'll become "the type of person who exercises", making you more likely to eat better, save money, waste less time, and have a positive self-image. Plus, you'll look better, which means you'll make more money and you'll get more attention from the opposite sex.
Just like exercise, eating well is great because of the health benefits. Fat loss, muscle gain, more energy, less feeling sluggish for an hour after lunch. And on top of that: you'll save money because you cook at home more. You waste less time browsing at the grocery store, or choosing off a restaurant menu, because you're narrowing down the range of choices you have. (Should I get chips or chocolate? NEITHER!)
Spending less than you earn is good for the obvious reason: that it prevents you from getting into debt and hurting your credit, paying money in credit card interest and overdraft fees, and so on. No arguments there. But there's other advantages of having cash on hand. You can usually get a great deal on bigger purchases if you can offer to pay in cash, right there and then. You can take advantage of business opportunities that need a bit of capital up-front, or do things that have a smaller short-term payoff, but a big long-term payoff. You can afford to take a different job that might pay less, but makes you happier. You spend less time worrying about bills and juggling payments, freeing up mental energy to spend elsewhere. With money in the bank you're less stressed, and you sleep better, so you become healthier.
With those three things in place, you're giving yourself a great base to work from. A solid foundation in your life. And the great thing is that each one makes the others easier: they multiply together healthy, energised, strong, productive, and able to take advantage of opportunities when you see them.