I want to start working as a photographer on weekends?

[AR]

I'd describe myself as a boyond-amateur photographer, but not professional. I have an idea to earn very little money by doing photosessions in London on weekends. I've seen good photographers who are asking for 100+ pound for an hour, whereas I could do it for 25-30 pounds in hour. Since I believe I'm decent photographer, I think some people could be interested in my photos. But here comes the main problem, how do I find clients? Where should I advertise myself? Facebook or twitter are not very suitable for me because I don't like being annoying and using friends as an advertisment.
Any suggestions how to get noticed?
If it appears that I'm not what I think about myself, anyways I feel like I should give it a try.

If anyone is interested, here's a few of my photos: http://500px.com/akalikin

I do want to emphasise that I'm going to do low-cost sessions, which technically should not affect the quality or my interest. This is just the amound of money I'm ready to work for to be happy for now