Hello, I have been having trouble sleeping the night before I have to get up really early (for school or work) I get nervous. How can I sleep better?

Shut systems off. 90mins before lights out make sure you start system shut down- no major activities- no exercise; work or strong emotional conversations; avoid bright direct light like from computer pads; phones; if you watch tv only quiet content. Try taking a hot shower with calming scents lavender; your room should have low light. Download and use progressive muscle relaxation audio instruction after lights out.
Sleep hygiene. Try any that apply: 1) Keep a regular sleep schedule (same time in/out of bed), 2) quiet, dark room - no TV/music, 3) use bedroom only for sleep, 4)if no sleep in 20min, leave room until sleepy, then try again (repeat as needed), 5)No caffeine after noon(includes chocolate), 6)write worries in a journal by bedside, then deal with them next day,7) Relaxation audio download as mentioned by Dr. Braun.
Sleep hygene. The first step is to try to arrange 1) for a dark room 2) no tv or computer 3) quiet 4) a cool environment 5) regular bedtime. This is often quite enough. Addressing the anxiety is a next step.