Self-published author is Kindle's biggest seller As an experiment, Wilkinson decided to put out the novel - the plot involves a body found in a locked house with seemingly no way in or out - via Amazon's Kindle Direct Publishing tool. His strategy involved selling the novel for 98p (the follow-ups cost more), setting up his own website and utilising social media, but he said: "Ultimately, I think any success they have had is that the books hit something of a gap in the market. Jessica, the lead character, is a strong-willed female so it's not a traditional detective story with an ageing bloke. Wilkinson received 30p from each sale of Locked In, and has earned just over £50,000 from that novel so far. Royalties from the other books are coming in. The next two books in the series, Think of the Children and Playing With Fire, are due for release this year. Gordon Willougby, European director for Kindle, said: "This is a significant milestone for independent publishing in the UK and we are extremely excited to see authors benefiting from the success of Kindle. We look forward to helping many more independently published authors achieve similar levels of success in 2012. Hoping to emulate Kerry Wilkinson's success by publishing your own novel? Here he gives some words of advice on getting started - and not giving up the day job: I've only ever tried to do my own thing. I wrote a book I thought I would like and enjoyed doing it enough to write follow-ups. I had no expectations for it and so this has all been terrific. The only thing I would say is that you should write for yourself, not because you think you can make lots of money or have a bestseller. I've been writing while working full-time as well - which is hard! I would get up at 5am, write for an hour, drive an hour to work, work for 10 hours (including around 35 minutes writing on my lunchbreak), drive for an hour home, then write until 10pm or 11pm until I went to bed. Then again the next day. But I've done that because I wanted to. With self-publishing, you run everything. Although traditional publishers have contacted me, I've not had any concrete offers I might be inclined to go with. Because of that, I don't know how long-term this is. I have no idea if I can sustain myself through self-publishing. I've done pretty well over six months and have lots of things going on but I'm a realist. The truth is, I probably could sustain myself for a few years but I have a great career too. I work as a sports journalist for the BBC and am surrounded by wonderful, creative and talented people. I love working - and it's not as if my job has slowed me down when it comes to writing.