Exit the conversation early. This one might surprise you, but assuming you're having a first conversation with a woman you don't know (whether a stranger or a friend of a friend), cut it short. By doing this, you're ensuring you're not misreading the situation and wasting her time, in the event that she isn't interested, but you're also demonstrating that you respect boundaries and aren't a threat to her. And if she was enjoying the conversation, you'll leave her wanting more.
Similar to the hobbies and special interests we all have are our political, religious and/or spiritual affiliations. Many groups that fall into this category also have single sub-sections for their members looking for a mate, whose special events are excellent places to meet people. There are even specific volunteer organizations geared only towards singles that you can join, knowing that while you are donating your time to a worthy cause, you'll also be expanding your personal network to include other, like-minded singles also looking for a date
Whether you are taking a couple of courses to upgrade, are a full-time university student or are passionate about tole painting, every community both large and small have courses you can take that will not only net you more knowledge but a whole new set of people to meet and interact with. If money is an issue, think about taking a class without getting credit or look into how old you have to be to receive free classes, since many universities now offer tuition-free options for seniors. And while you want to take classes that you have a personal or professional interest in, it never hurts to take something you normally wouldn't - if only because you have a hunch the type of person you are looking to meet would take that kind of class