I'm considering going into sole-practice, and the time of year makes me think of wetting my feet by offering a Last Minute Self-Assessment Tax Return Service.
The idea would be to offer a cheap service (for the sake of winning a handful of clients quickly, and with a view to getting some experience rather than worrying about serious profit) and churn out ideally 10 to 15 self-assessment returns in the back two-thirds of January. (I think a mini-practice could be set up quickly using ICAEW-template engagement letters and micro-professional indemnity insurance.)
However, rummaging up 10-15 new clients is likely to take some work / advertising. (I envision them all to be anxious about 31 Jan, and willing to latch on to the bargain fee - say £100 to 150 for returns with not too much complexity?)
Any advice for how to get the word out there, and get my proposition in front of enough people to win some work?