Hi im a full timer .... i sell through photographers direct my web site galleries etc, i do everything ( well nearly ) advertising, gigs, prints, weddings, engagements etc and some design for CD covers, to make it your main income you need to be able to do a bit of everything in my humble opinion, tuition and photo days can be good as a full time income too.
i totally agree with Alistair about the micro agencies (dont touch them with a barge poll) they devalue not only yours but others work and ruin and cheapen the market! so much so you may as well set up a car boot sale stool and knock your pictures out for 20p each
good luck genese