As often happens, I found some inspiration from a post at Dean Dad's...
When I was an adjunct it took me a whle to figure out a few very key things... After I got these down, it became easier for me to handle the adjunct game.
1) Don't rely on having anything more in your classroom than some walls and desks and plan accordingly. Likewise, make any copies well in advance, as you have very little pull with the people who can fix the copy machine.
2) If it isn't in writing, you won't get it. This goes for TA support (never had any... still don't), and other things like rooms and technology.
2a) Make friends where it will help you, with the support staff! I was quite lucky at one of my main Red State schools to have made friends with the department secretary who also functionally ran the department. I got a good (close) room, the class schedule and assortment of classes I wanted and a decent office because she made the assignments and she liked me.
3) My ethical committment was to the students, not to the college or the department. My committment to them began the first day I got paid, and ended when grades were submitted.
3a) Avoid giving incomplete grades, as you don't know if you'll be around to change the grade later if necessary. Tell the student this and if they complain, tell them to go to the department chair or (if their parents have clout) higher -- explain the adjunct system and tell them that you would be happy to change it later IF you are around -- but that it isn't at all a sure bet.
4) Going to meetings for things that are beyond the scope of your classroom and/or length of contract is a waste of time. Often the department doesn't care what you think, as you may not be around to live with the implications of any given vote. Generally, these people didn't work too hard to hire you and they realize that you got the job because you were sucker enough to take it and you were available. To them, you are some odd category of 'other' faculty....
4a) Also, these meetings are great places to lose your job --- if you get on the wrong side of the politics, suddenly you won't be an adequate teacher and not renewed --- I saw it happen to several friends.
5) Always look elsewhere for teaching opportunities and don't turn any down unless they conclict with an already scheduled session. When you turn them down, tell them why and that they need to ask earlier next time. If you do your job right, you can be the first one they call for sections and won't have to wait until the last minute to know what you are teaching.
5a) think of yourself kind of like a free agent --- only the system sucks. You do have what they need, you are a competent and qualified person that will teach classes they don't want to teach or can't teach themselves. If you keep your head down, do your job with as little fuss as possible and are reliable, you'll be able to choose when you move on and they will let you go fondly, as they understand that they couldn't have you forever.
6) Try to get as many different kinds of sections as possible. If you have several divisions within your discipline, make sure you teach as many of them as you can. Smaller departments are looking for people who can teach a variety of courses, so although having a variety of preps is harder while you are doing it -- you are doing what amounts to a teaching internship and it would be doing yourself a disserviceif you fail to get the most out of it.
6a) If you have the opportunity, teach in as many different kinds of places as possible. Try to get in the the SLAC, the larger university and the community college. Try to get to teach different ethnic groups, socioeconomic groups and urban/rural situations. This will give you experience with any kind of student -- and make you more employable as a result --because you'll be able to say, "yes -- I taught non-traditional black students at X school, their population was much like your's -- these are the challenges I faced and I overcame them by doing X".
7) Don't make too much work for yourself. Figure out ways to save time in prep and grading and use them shamelessly. This may mean skirting the department rules -- but chances are good that nobody will find out :).
8) As soon as you have your schedule for the following semester, tell your students what else you are teaching that they could take from you. Getting a core of students who take another class looks great to the department and makes it harder for them to change your section at the last minute as you can tell them that they'll have to explain the change to the students who expect you to teach the course. It also is easier for you if you have some repeats, as they can help the others figure you out and you know them..
Adjuncting can be decent if you have low expectations, keep your professionalism even when they aren't treating you as a professional and make the connections with your students.