I was pretty fortunate as I didn't have a business model, I was playing at domain sales and affiliate marketing. I arrived on the scene around the time of Google's attack on EMD's and Nom's .uk plans so my fledgling business died before it started.
From my perspective seasoned domainers and affiliates discussed and debated the changes to their business in public, this was an excellent education for me and led me down the path I now follow. Sort of learning by others mistakes.......
I can't remember who or how many on here advocated building something useful but it was excellent advice. Once you get past the "quick buck" mentality and start building something useful Google, EMD's, Panda ...blah blah blah become irrelevant and you can focus on building a business you can control regardless of outside forces.
Going forward, building an authority site which is useful, unique and Google proof is the key. No half arsed attempts, no cutting corners when your project is working and part of the public psyche you can use targeted affiliate programs, your own products or a whole host of other income generating models but you decide not G.
In relation to domaining, it will always be a hobby for me as I genuinely feel it's not an option for newbies unless they have very deep pockets. I've tried to find the opportunity in .uk proposals and frankly I just couldnt be arsed with it, better spending my time doing something I can control like building an authority site as above.
Regards
Rob