Investing in promising people that are new to the industry - the easiest way to do this is through Twitter. I've found some amazing new developers which have great mindsets that I knew would do well in their careers, which I've capitalized on by following them early on and having regular chats with them about what they're working on, etc.

It allows you to maintain leverage in your field because once they're successful, you both already have a relationship and it becomes a lot easier to network and strike deals.

It has a huge upside with almost no risk - all it takes is a Twitter follow.