Really really simple procrastination trick that works wonders for me: don't just minimise the browser when trying to work, close it. If I need to use it for something work-related, one tab only and close it again immediately afterwards. The trick here, I think, is that flipping to the browser window is an automatic reaction when I get stuck on my work. If my mouse goes to the taskbar and it isn't there, the extra moment required to think: "Oh, I'll have to relaunch it" is just about enough to override the automatic reaction with: "No, I'm working".