Your users have problems. Write about solutions. Eventually you'll want to scale this, but for now, start writing.

For example, if I hypothetically ran an innovative photo sharing site, I might assume that there exists, somewhere, a busy mother who wants to get baby's first steps to her grandparents who live in another state, and I would list up every possible thing I could think of that would frustrate that mother, and then I would start knocking them off the list. Bonus points if I actually knew a busy mother. (I do, but if I didn't, I'd probably find one.)

Then, after putting that up on my site, I might ask my busy mother who she reads. Oh, mommy blogs? Wonderful. (And a little terrifying -- those of you who work with mommy blogs understand.) So I'd try to learn a bit more about mommy bloggers, use Peldi's approach for emailing, and try to convince them that their readers will have even more loving, peaceful relations with the inlaws if only they had read what I have to say. Maybe they would be interested in a guest post, or in linking to my pre-existing series on how to solve their issues with getting baby photos to grandma?

Note that I could do this well in advance of actually having a photo sharing site running if I were so inclined. And I could do it for audiences not limited to mothers. And I could probably get someone other than me to do it, too.

The best way to start marketing is to start listening to anyone who will talk to you.

Start with a list of needs or gaps that you feel you understand or are very interested in and then talk to anyone you can about them. During the conversation try take the person through the experience of the problem you are trying to solve. See how quickly they get it, or if you have to illustrate that it is a problem or need. Then ask them how they might go about solving the problem. Now bounce your solutions off of them and get their take. Now challenge your ideas with theirs, did something better emerge? Do this enough and it is called upstream marketing. If you want to get crazy, try to pick solutions that have an obvious way of making money.

If you don't have any ideas that you are in love with yet, start a bug list. Simply write down everything you find that bugs you, no matter how trivial or personal. Do this for at least two weeks to get comfortable with challenging the way things are. I find people's bug lists start getting interesting when longer than 100 entries. Pick your favorite bugs and brainstorm them into opportunities (solutions) then start talking to people. By all means, brainstorm with friends or business partners.

I typically talk to my friends about ideas first, usually over cocktails. Even my best friends are still pretty biased towards being supportive though, so they are just the first sounding board. It is important to follow up with strangers or other people not unreasonably incentivized to be nice to you. I used to hate going to parties with people I did not know, but now I find I am liking them more and more because I can learn a new perspective on what I ideas I am researching at the moment.

A great technique for finding people I had to force myself to get into is cold calling. I use linked in, my personal network and even just e-mail people on their contact pages to get leads. I am still surprised at the number of people who take me up on coffee or lunch for the promise of a discussion about something they are interested in. As a bonus I have met some great mentors this way.