I’ve taken the evening off (well, the whole weekend really!) and been fortunate enough to stumble across a couple of really good pieces of advice.
1) According to Kyle Gabler, of 2D Boy and World Of Goo (now available natively on Linux) fame, if you care a lot about a project it usually ends up sucking, whereas if you don’t care if you totally fail it’s much easier to make awesome stuff.

2) According to Sergey Brinn, no introductions needed, one thing that Google did in the early days was to focus not on how their product would change the world, how many people would use it, or how much money they would make, but on making the best search engine they could. OK, not really advice, but I took it as such and think just focusing on the task at hand, not getting ahead of yourself etc etc etc is.