Not a nurse, but have been an EMT-intermediate for 4 years and am a paramedic student. Do lots of difficult IVs throughout the hospital when im doing clinical rotations.
1: prepare.... get everything you need organized, do it the same way every time, develop your own routine and rhythm for it.
2: take a deep breath before going into the room when you are new. calm yourself. if you find your heartrate high or are jittery take a deep breath, hold for 4 seconds, exhale, hold for four, and repeat.
3: confidence.... dont say you are going to try to start the IV. you ARE going to start the IV. calm yourself and the patient.
4: pick a site and a catheter size you think will work. It is better to stick once and get it than trying to get a big iv and having to do it 2 or 3 times.
5: usually you want to go right on top of the vein and 'land the airplane'. The angles in most EMS texts and I'm going to assume most nursing books are way too steep. try like a 25 or 30 degree angle, sometimes even shallower.
6: for those really tough wiggly ones try hooking the vein. puncture the skin beside the vein and the twist so you are bevel away from the vein and go in from the side. (easier to have someone show you than describe)
7: relax.... sometimes you get it, sometimes you dont, ask for help when you need it. if you miss and feel upset or frustrated let someone else help you as you will not be doing yourself or the patient much service.
8: lots and lots of practice.