A million dollars is still a tremendous financial milestone, and that much money could go a long way toward securing a comfortable retirement. A famous investor once said that the first $100,000 is the hardest, and then it gets easier.

That's true: Compounding starts taking control and doing some of the heavy lifting for you.

So if you're still grinding toward that first $100,000, keep going! It gets better. Whether you have your first $100,000 or not, there are multiple ways to get to $1 million in retirement savings. The cool part is you have various tools at your disposal.

Here are four of them and how they can get you to that million-dollar mark. 

1. Get a side hustle

A side hustle is a secret weapon for building wealth. It doesn't have to be a second job, consume much time, or make much money.

The important thing is that whatever it makes, it goes toward your nest egg -- a dedicated revenue stream pouring into your financial future. It could be a gig that makes $1,000 per month. How much could that turbocharge your savings? 

Quite a lot. Suppose you have $100,000 invested, which grows by 8% annually on average. That $100,000 alone would take approximately 29 years to compound to $1 million. But thanks to your side hustle, that drops to just 20 years -- almost a decade sooner. Don't underestimate the power of additional contributions and how a small gig can impact your savings.

2. Set it and forget it

For those willing to be a bit bold and lean heavily into stocks, you might be able to achieve a higher rate of return, which means you'll reach your financial goals sooner. For example, the S&P 500 is an index of 500 of America's most prominent companies. This index continually changes, which has made it an effective wealth-building tool.

The index can be volatile; the S&P 500 might go up or down 20% or more in a given year. But it averages about 10% annualized returns over decades. Now, doing the same math as above, it would take your $100,000 just over 23 years to hit $1 million without additional contributions.

You have to deal with volatility, but the S&P 500 and the broader U.S. stock market have overcome wars, recessions, pandemics, and crises to continue moving higher over the long term. Consider investing in low-cost index funds that track the S&P 500. 

3. Save on your taxes

There are various investment vehicles to encourage people to save for retirement. The most common plans are the 401(k) and individual retirement account (IRA). These incentivize you with short-term savings by deferring taxes on your contributions until you withdraw the money in retirement.

Some special vehicles, such as a Roth IRA, require you to pay taxes on your contributions, but let you withdraw your qualified funds tax-free in retirement. Consult a professional if you're unsure which retirement accounts make the most sense for your financial situation. But at the end of the day, be sure you're not paying more in taxes than you need to.

4. Get free money where you can

Some employers will match a percentage of your retirement-plan contributions, called an employer match. Some online brokerages also offer matches on retirement plans. This is free money, requiring only that you contribute your share. Think of it this way: Any matched dollar essentially doubles (assuming a one-to-one match) before generating any market returns. It doesn't get any easier!

Of course, there is always the fine print. Many matches require that you stick with that employer or brokerage for a set amount of time to keep the match, so you must know all the rules before you get into something. Still, a match is a powerful boost to your savings that is worth checking out.

Putting it all together

Remember, you can use multiple tools to build a stellar financial plan that will carry you to millionaire status in retirement. Consider combining all these tools. Have a job on the side and dedicate the revenue to your investment portfolios. Explore and use retirement accounts, both individual and through your employer, and grab that match if available.

Do all this, and you will be surprised by how much wealth you can build throughout your life.