AngelList is your best bet. Since you're asking the question, chances are you don't have a way to get introduced to these investors. The simple truth (like it or not) is the chances very low that you'll get a deal done without an introduction from someone they trust. AngelList can help with that, so can going to networking events. And finally, If you're the introverted developer type, you can also get their attention by just building something really cool on your own, followed by some serious traction. Arguably the best strategy of them all.