1. Know your number

"Retire early" is a great goal, but what does that really mean? Spend time creating a retirement budget, a realistic and detailed one, and then figure out how much you need to save in order to meet it.

2. Life below your means

Retiring at all, and especially retiring early, requires you to be extremely budget-conscious. Find ways to reduce your current expenses so you can save as much as possible, like eating out less, vacationing nearby and more. Figure out how much you can save monthly, and have that amount automatically transferred into an investment account so you aren't tempted to spend it.

3. Gather 'free money'

Be sure that you are getting the maximum amount of matching dollars that your employer provides and use credit cards that can make cash back deposits into your brokerage account.

4. Maintain a diversified portfolio

The only way today to keep up with inflation and have a chance of your assets remaining in your 80s is to utilize equity mutual fund aggressively.

5. Figure out what to do for health insurance

If you retire early, you won't be able to receive Medicare until you are 65, so it's necessary to find coverage in the meantime. You can stay on COBRA up to 18 months after retiring, but afterwards you'll need an individual policy. For perspective, the average couple spends over $200,000 for health-related expenses in retirement. The Federal Health Insurance Marketplace is also a great option and is less expensive than a COBRA plan.

6. Don't automatically roll your 401(k) to an IRA

A rollover is generally a good idea if you're over age 59, because at that age you'll be able to withdraw money without a penalty fee and have access to a much broader tang of investment options. To avoid penalty fees when you're under 59, maintain your 401(k) and rollover in the later years.