She went from being a deeply indebted college grad to having a credit score in the top 1%.

Out of college, Lynnette Khalfani-Cox was a financial mess. She racked up over $100,000 in credit card debt—plus student loans. And as a cash-strapped grad, her payments were rarely on time.

At one point, Khalfani-Cox even had her car repossessed.

I know it sounds awful, dont judge me, but its the truth. So Im pretty sure that my credit score was somewhere in the 400 level,” she wrote in her blog.

Fast forward to today, Khalfani-Cox is among the top 1.6% of Americans who have a perfect 850 credit score.

How did she do it? Not by winning the lottery or inheriting a fortune, but by changing her money habits and applying simple yet often-overlooked credit rules.

In this article, youll find four key principles that helped Khalfani-Cox and other everyday workers achieve the highly sought-after 850 credit score.

A long credit history

Lets begin with setting realistic expectations.

There isn’t a one-off fix that can improve your credit score and instantly get you to that perfect 850. Its an ongoing process that can take decades. In fact, scores over 800 can sometimes take 20-30 years to achieve.

In 2011, SubscriberWise, a credit reporting agency for the communications industry, conducted a study of credit agencies. It found that the average length of a credit history for 850 scorers was 30 years.

John Ulzheimer, another member of the 850 credit score club, said that some people simply cant ascend to 850 because their credit history isnt old enough, even if they do everything else right.”

Dont be discouraged by these stats, though. You can still achieve a better-than-good” credit score in just a couple of years. Thats because the length of your credit history accounts for just 15% of your total credit score (according to FICO).

But if your ultimate goal is to hit the top score, the key is to start as soon as possible.

Keep your credit utilization rate low

Credit agencies look closely at how much of your available credit you are using (in financial lingo, “credit utilization rate”). So don’t max out your credit cards. Try to keep any balances you carry well below the limit on each card.

The less you borrow, the better your score on the credit utilization rate.

But how low should you go? And how can you keep your credit utilization rate under control?

The Consumer Finance Protect Bureau states that the fastest way to build your credit score is to use just 30% of your total credit limit:

“…dont put most or all your credit card balances onto one card; it may hurt your credit score if this means that you are using a high percentage of your total credit limit. Experts advise keeping your use of credit at no more than 30 percent of your total credit limit. You dont need to revolve on credit cards to get a good score.”

For example, if you have a card with a $1,000 limit, you’ll want to only use up to $300 each month and pay the full balance at the end of the pay period.

This will show that you can responsibly handle credit and manage your finances.

Mix it up

On the other hand, taking on debt isnt necessarily a bad thing for your credit score.

More debt can actually help if you keep it within your means and mix it up. It sends a message that you are credit-savvy and can manage more than one account.

Khalfani-Cox, from the financial zero-to-hero story says, When you show that you can responsibly juggle all those types of loans, you get brownie points for that.”

That doesn’t mean you should rush out and snap up every possible loan.

Its best to gradually build a good credit mix as you go about your life. Just remember: as good as having a mix of credit is, multiple credit lines can be difficult to keep up with.

Make sure you dont take a bigger bite of credit than you can comfortably chew.

Pay your bills on time—every time

This one falls into the Mr. Obvious” category—but if you shoot for a perfect score, you have to pay all your bills in full and on time, every time.

An oilfield worker named Shawn Nelson attributes his perfect score to his steady employment over the years. Having a steady job and being able to pay your bills on time — I think thats where a lot of people can get messed up, if they’re out of work for a while….”

Easier said than done.

There are times when the money is simply not there. Or sometimes that one pesky bill slips your mind—especially if its something like a small credit card balance.

It only takes one late payment to damage your credit score and months or years to repair it. So, here are some tips for you to stay on top of your bills:

  • Create a budget and list all your bills
  • Automate all your payments so you dont forget
  • Build an emergency fund. It can be anywhere from $1000 to 3-6 months of living expenses

Creating a budget and automating payments will help you keep on top of your credit and hence your credit score. And having an emergency fund can help you stay on your feet even during tough times.

You can do it, too

If a fresh grad with $100,000 in credit card debt and a repossessed car can achieve a perfect 850 credit score, so can you!

The key is to create a plan and follow it. And dont worry too much about getting a perfect 850. Khalfani-Cox and Nelson hit that max score only for a short time.

Besides 850 isnt essential to get the best loan terms; lenders consider anything above 800 excellent.