Angel investors are really the first or second step to funding a company. In my experience, angel investors can be institutional and structured groups investing in specific applications, or just wealthy people looking to diversify. I've seen companies raise $250,000 spread between 10-12 investors.
Where do you find them? Anywhere. Usually where rich people hang out. That can vary from countless networking events, country clubs, speaking engagements, business happy hours, and more. Also, accountants and lawyers have a large network of high net worth colleagues, peers, or clients that are always looking to make money. A lot of times if you can start networking and becoming close with people like this (and if your idea is good), they can play a role in helping you find cash.
The biggest thing entrepreneurs overlook when raising money is the relationship. All too often, entrepreneurs think that all of a sudden money will show up with a good spreadsheet or slide deck. It takes countless calls, meetings, emails, and conference calls for angel investors to build trust and eventually find a deal. Keep working hard and keep your network big and the money will eventually come!