Bankrate spoke with a number of financial experts to break down the top ways to set up your 401(k) to thrive in 2021 and beyond. This is the second of three columns outlining actions you should take.

Action 2. Grab all the free cash

"To get started on a tangible level, take a look at your company's 401(k) options," said Kevin Driscoll of Navy Federal Financial Group. "Many companies offer an incentive match, encouraging you to invest part of your paycheck into a retirement fund. Whatever they match, put that percentage into your retirement fund – it's free money."

The incentive match is one of the best parts, maybe the single best, of the 401(k) plan. And the employer match is the easiest, safest money you could ever make, offering you an immediate return for doing what you need to do anyway.

Many employers will match 50 percent of your contribution and sometimes as much as 100 percent up to a certain amount. A few employers do even better than that, although many employers do not offer a match at all.

"Ensure you have contributed enough to get the full company match," said Kirk Kinder, certified financial planner at Picket Fence Financial in Bel Air, Maryland. "There isn't any legit reason not to get the full match."

Action 3. Get more aggressive

If you have a long time until you retire, you're probably going to be better off having a portfolio that's more aggressive. That means your portfolio will likely have more stocks in it and fewer fixed-income investments such as bonds and CDs. In fact, if you're more than a decade away from retirement, it could be a huge mistake to be too conservative.

Over time, a diversified portfolio of stocks can return more than a typical bond portfolio. The Standard & Poor's 500 index has gained an average of about 10 percent annually for decades. And with retirees living longer than ever, they're going to need to ensure their investments offer a high rate of return.

Many 401(k) plans have target-date funds that automatically shift your aggressive assets into safer ones as you approach your retirement date. These target-date funds can be a good solution for investors who don't want the hassle and headache of managing their own portfolio.

"I'm a big fan of target date funds," says Mark Wilson, founder and president at MILE Wealth Management. "Most of these are well-diversified, wisely built, and auto-rebalanced. Unfortunately, I often find that they are too conservative."

Wilson recommends using a target date fund that's 10 to 15 years longer than when you expect to retire, because it will have a greater allocation to stocks.

James Royal writes for Bankrate.com.