The short answer is you'll need lots of money (typically minimum investment per company of $25K), and/or connections + be able to add value in other ways (as an

The short answer is you'll need lots of money (typically minimum investment per company of $25K), and/or connections + be able to add value in other ways (as an advisor, etc). Alternatively, you may be able to find some of these companies on AngelList Syndicates, FundersClub, etc, though I think you'll still need to be an accredited investor.