Any suggestions for a 20 year old investor with a new 401k?

If your contributions are not being matched by your employer, you should consider putting less in the 401k and putting the money into an equity indexed universal life plan. There are no limits to how much you can add each year and the money compounds tax free. When the market goes up your balance goes up. But when the market goes down, your balance stays the same. Best of all, you will be able to access the money at retirement free of income taxes, thanks to zero-cost loans. You will build a tax-free retirement income that you cannot outlive. Talk to a licensed life insurance agent for details. Best of all, you won't need to worry about managing your money personally.