Alis and David have both written recently about the things they find most difficult about writing. I am completely flabbergasted by Alis' issue with openings, and side with David slightly on the middles, but my biggest hurdle is most definitely research. If it was just one particular bit of information, then that's not a problem, but on the latest book I'm writing I need to know the ins and outs of Mexican gangs and drug trafficking (have a bit of knowledge on that already), European arms dealing circa 1999, the ins and outs of British local council operations and UK and international property law, healing time for a severed tongue wound, as well as the history of Sierra Leone, Liberia and Serbia during the Second World War. Oh and all about horses. Write what you know. Good advice. (To be fair, I know a little about most of these topics, but the local council politics is the thing I'm finding most daunting.)
So why not stick to SF, you cry? There's a whole other can of worms: heat- and solar-activated computers, artificial intelligence, nuns, cyber-gypsies and steampunks... It's the same problem wherever my pen takes me.