I have a philosophy on contracting that is shared by some, and not-so-shared by others; nonetheless it appears to be a rather successful one so I thought I'd share it right quick (this won't take too long).
The idea behind contracting work is that you are given a job because you are seen as a smart business move - not because you're somehow smarter. The important thing to remember here is that you are not considered technically better (more capable of user the computer, of learning, etc.) by any stretch of the imagination by the one cutting your check than anyone else on their internal team. What I mean by that statement is that, even though you are getting the job, you ought to consider that many people inside the team that's contracting you could also get the job done too. Even if they (those paying for you) don't see this, you ought to always think that way. What makes you valuable is:
1) Your autonomous capabilities,
2) Your one-time use and disposability,
3) Your speed,
4) Your knowledge/experience
Each one of these factors boils down to one simple thing: money. Given your autonomous nature, the people contracting to you expect that they can treat you as relatively hands off for small periods of time and that you are capable of using common sense to achieve goals with the rest of the team. Your contractee is expecting that you are not going to go "off into the weeds" all too often, that they won't have to babysit you, and that you'll be able to show results relatively fast. Your one-time use and exposability is important as those paying for you only have to be responsible for you during this particular project - they don't have to pay for health insurance, they don't have to worry about someone stealing you away - all in all you're seen as fairly low risk. These are important factors, but the most important are the last two that I mentioned: speed and expertise. You are, by the hopes of those buying you, a catalyst for the project - you are the molecule that, when snapped into the rest of the project, speeds the reactions and gets the thing done.
So, these are all kind of introductory thoughts - but what is my philosophy? My philosophy is that if you're getting paid to work at X dollars per hour, you ought to constantly judge your work by that rate; and so if you have a bad day, or you suddenly become an ignoramous about something and fail to get something done by your own internal clock - you charge less (in other words, you don't charge for the hours you spend screwing up, only those you spend doing something right). I'm an optimizer, I prefer to think in terms of how something can be done more effectively the next time around - and so I only charge for what I think I'M worth, and my judgement system is often a lot harsher than anyone else I've met. The result: less wack-off'ery and more focus as you suddenly tell yourself "I shouldn't just dork around on this project, because I'm only going to pay myself what I'm worth" - I find that every project I'm on I get to understand my limitations better, and gain a hell of a lot more focus and effeciency. I'm a huge fan of building into my environment certain external pressures and realities that keep me focused - reality doesn't waver (like an alarm clock), however we often do internally.
Another interesting side-effect of this philosophy is that my endeavor to understand things is highly restricted during 'contract mode'. Contracting is about application - you ought to be applying your talents when the stage lights are on, not uncovering technologies and learning how to use them: you are under the gun, and they aren't paying you to appease some inner demon (daemon?) to get to the bottom of things and figure out how they work. This reminds me of the days back in high school when I used to try out for honor bands - when I would audition, I would perform what I practiced; and I never asked myself, "Man, I wonder why Bach decided to use this particular chordal progression".
The reason some don't like this philosophy of mine too well is that, as contractors, we are here to make money - which often means hours (paid by the hour). The thing is, though, that you ought to look at the world four dimensionally (that is, by including time) and realize that,
1) You really don't want to be stuck on this one project forever,
2) They don't want you stuck on this one project forever
...basically, my theory is that if you get one job done well, there'll be more waiting for you. Don't try to suck all your money out of one project or look for that golden project - look for continuity instead (you can always get dropped, remember that).