Check the crash cart until you know it from memory.
Think about "what if" situations, what would you need, and where would you get it. Mentally rehearse your actions, and you'll know what you need to research or ask about before the crisis happens.
Slow down. In a crisis it's tempting to rip everything open, and in actual fact nothing gets done, no brain cells are actually functioning. Ever run into the supply room and not see the equipment that's right in front of you?
There are usually lots of people at a code. The doc hollers out "I need X!" You yell "I got it" and then go do it- just that one thing, and try to block out the chaos. You will be more likely to hit the vein, or find the equipment if you concentrate. Pick something easy, be successful, then move on to the next task.
You can't hurt someone that is already dead, do your best, think about how things could have been better, but don't go on a guilt trip. Guilt will make you clumsy next time, but honest critiquing will make you smarter.
No one is expecting you to do everything. If it's my patient I stand back just a bit and try to coordinate and delegate. Call for the NGT once the ETT is placed, make sure the suction is available for ETT and oral, and NGT, keep track of that little white connector on the NG, and the tape roll, and the 10cc syringe with your eyeballs. Think about the pt history and how it fits together, and what you will need once the patient gets a heartbeat (respiratory, Xray, labs, another IV, drips made up).