A lot of answers depend on marital status, # of kids, type and amount of debt. Before you get crazy investing, do the following 4 things. This is my thoughts without knowing any specifics (Me and wife are both 40 so not much older than you)
1. Save up a bit of cash for an emergency. Amount depends on your risk tolerance/,occupation, etc.
2. Contribute to 401k at your employer up to the Company match. I'd lean towards an index fund (Vanguard or Fidelity is good). Beware, there's a lot of bad funds in 401ks so a Target Date fund there might be crap. Dont give up the free money with Company match. Morningstar is a decent site to analyze mutual funds within a 401k.
3. Knock out your non-mortgage debt. This may involve extra shifts, side hustle, selling stuff, detailed budget. This part will be painful.
4. If married/kids, make sure you have enough life insurance (term life) in case you die.
Once you have done those 4 things, I'd open up a Roth IRA. You (and spouse, if applicable) can each contribute 6,000 per year. That's $500 a month. Just have it taken out each month. Fidelity, Vanguard, T. Rowe Price, and Schwab all have low cost index or target date funds. If you cant do $500, you can do smaller amounts. All 4 are really good.