I would make up my own typed (wordprocessed) page to carry around with me that has the following information on it. It should be a work in progress that you will change many, many times to suit your current needs. The main purpose is to have this information at your fingertips:
A list of frequently called telephone numbers so you won't have to keep looking them up: pharmacy, radiology, lab, dietary, central supply, transport, ICU/CCU, specific doctors that you might be calling all the time. Also include your manager's number.
Normal lab values (electrolyte, BUN, creat, CBC, PT/PTT, therapeutic Digoxin level, and ABG's)
A list of questions to ask when assessing someone complaining of chest pain so you won't leave any out
An abbreviated list of a ROS (review of systems) and body systems to assess during a physical exam.
A list of things to review and have in front of you before calling a doctor
Eventually, you will want to add the hospital protocols you will be using frequently (hypogylcemia, Heparin, arrhythmias)
I often printed mine out on a piece of colored paper (green or hot pink--you can buy them in individual sheets at Kinko's) so I could identify it quickly on my clipboard that I carried around with me all the time. I also used clear contact paper to cover them so they were protected from getting wet, wrinkled or ripped. In a pinch, you can plaster something onto your clipboard with a piece of Tegaderm--works really good!
You will eventually need a pair of calipers in order to evaluate and diagnose rhythm strips, but you don't need them on the day you start! I always had my own because the community ones were never to be found when needed in a pinch (Murphy's Law must be respected!). A pair or even two pairs of hemostats are incredibly useful tools for all kinds of little things that need holding, tweaking, tightening or loosening. I have ones with curved tips as I think they get into smaller places much easier than straight-nosed ones. Have at least 2 pens in your pocket in case someone wants to borrow one and never returns it. If you don't keep a clip board with you, keep a folded up blank sheet of paper in your pocket on which to make notes, otherwise you will end up using paper towels to write things on. I think it's also a good idea to eventually find a nice flexible ruler of some sort because you are probably going to be measuring circumferences of legs and bellies and perhaps even some incisions. Fabric stores used to carry a nice retractable one that fit compactly in a pocket. You don't want to be carrying your purse into the facility if you can avoid it, so have some little coin holder for the vending machines and the cafeteria. You probably already have a watch with a second hand. Make sure your stethoscope is marked with your name.
Just a last thought. Try to remember to stick your hands in your pockets and check what is in them before you leave your unit to go home. Make this a habit so you won't accidentally walk off with narcotic keys or a pocketful of tape you don't need.