Hi there,
thanks everyone for your replies, as they are useful for me too! I am also recruiting a specific patient group, but I need a much smaller number of "subjects" (purely qualitative approach). So far I have found some people through internet support groups, and one through a friend of a friend. As these sources seem to have dried up (it is a topic that many don't wish to speak about), I will next be leaving "posters" in waiting rooms. I will also be e-mailing all of my friends and everyone I know, for them to spread the word. I am hoping that some know someone who knows someone...

I have so far not offered any incentives when recruiting. Those who I have already interviewed all said, without exception, that they felt rewarded simply by having someone to talk to about the things they would normally keep to themselves. I do give them small gifts (such as a pretty paper notebook) as a token to show them that I value their willingness to participate, and also to keep them happy, as I conduct two follow-up interviews with each participant. My interviews are meant to last an hour each, but some have taken longer - I would never cut them short, as they become longer when the participant "needs" to talk more, and in that way I am not just using them as my research subjects, but also giving something back - even if it is just an open ear.

Concerning ideas about how to design such a poster and what to put in it, I have been considering leafing through the appendixes of older PhD theses. That might help :-)