Since you are just getting started, it is simple!
Step 1: Max out that 401k. I don’t know your income, but if you aren’t maxing it out ($18,000/year + $6,000/year since you are 50+ = $24,000/year) you are leaving money on the table and paying too much in taxes.
Step 2: Max out your IRA ($6,500/year for people 50+)
Once you have maxed out both those account, you can start thinking about other ways to save/invest, but focus on those two items first.