[ericmay]

There's no great answer here. Even those advocating for something like a two or three-fund portfolio have to contend with great arguments for 100% equity allocations (https://www.gocurrycracker.com/path-100-equities/ for example - haven't vetted numbers myself).

But I do think I have some 100% guaranteed "advice" (this isn't financial advice and you would be stupid to listen to anything I write here) which is that you should always max out tax-advantaged accounts. It will depend on your income level and specifics, but you should basically max out your 401k and any IRA vehicles you have access too (depending on income level) with whatever you do. While the regulatory environment can and will change, based on what you know today and can predict, these accounts are huge up-front 0 risk ways to save even more money.

With all of that being said, generally it's advised to follow something like a 2 or 3 bucket portfolio with a mix of total US stock market (or S&P500) making up something like 90% at your age and then reducing by 10%/decade + emerging market funds + bonds. Allocations depend on goals/ideas.

Speaking of goals, the #1 thing to do is figure out your goals. Want to be financially independent at 35? Well you will want to put money into different accounts and probably different assets. Want to "work" until you are 50? That's a different strategy. Etc.

When it comes to investing, you don't get rich and then all of a sudden you are rich.