I think one of the most important tips is, "just use your device." If you're constantly watching that battery meter dropping, that is time you could have been using instead, that is stress you are creating. Checking with Battery Report, some days are reporting over 9 hours (almost 10) and one day is under 6, and a couple are about 6-7ish. It really depends on what you do to cause it to drain faster, so you can't keep checking that meter to see what happened.
A couple things though. Windows 8's Modern side is much more efficient as apps will tombstone if not used and will only use approved background APIs, thus it's managed pretty well. Think of being able to play music through the music app, but not having the app even open really, thus you're not use a lot of cpu cycles on keep the app open, just the api stream it needs to do its job. The big guzzlers besides brightness and what has been said are the desktop programs. Since those do not tie into the newer APIs they function essentially like they did in Windows before. Windows 7 was better at it, it would use less memory for minimized programs, but regardless, Windows needs to use more to keep the entire program running while its opened, unlike what it would do to the Modern UI side which it just needs to keep the APIs running instead of the apps. I think if you use mainly the ModernUI side you'll see that Windows 8 will run better on battery life, but if you're constantly on the desktop you'll probably see more of a hit, which is what I've been seeing with my usage (Citrix desktop vs Citrix ModernUI). One of the main reasons I can't wait to get Office in the Modern UI, then I'd have almost no need for the desktop (until a professional quality ModernUI art app comes around). At least that's how I've understood the impact of power draw on Windows 8.
Regarding the battery sizes, yeah the Macs have larger batteries, but you need to realize they are able to achieve this because of how they custom designed the boards for their devices. It was really something to initially see that the inside is almost completely taken up by battery. Whereas on the Surface Pro, it still seems like design inside could be better, whereas Apple's products really are machined well for it that it's almost like art.