As my long-term sub job ended today, I remembered something I want to remind all subs about. Don't forget to market yourself. Sure, you are in the sub system for your district, but if no teachers know you, you will be at the mercy of the random call. When you get a job, make sure you talk to some teachers around the school to make yourself known. And I highly suggest making yourself some business cards. And they don't need to be fancy at all.
You can certainly go somewhere and have them printed, or you could order them online through a service like Vista Print. But I made mine simply in Microsoft Word by using a pre-made template from the Word Document Gallery. I replaced a photo with a more "teacher-y" one, and added my information.
Make sure include the necessary information: your name (obviously), a district ID number if you have one, a few of your credentials, and your contact information. Then I print them on my printer using business card shells you can buy at any office supply store.
As I left the school today, I cleared with the principal that I could put my card in all the teachers' boxes. Now, the teachers can keep my card handy and request me the next time they need to be out.