Congratulations! Happy for you ! ER is a very interesting thing, either you like it or hate it! Definitely not for everyone
In regards of the resume, try to find out the name of DON of the hospital you are applying to, and sent her/him a complete package that includes resume, cover letter,references letter and copy of your certificates (specialty, ACLS, PALS, EKG, etc). In every hospital most of the hiring process is held online , therefore your resume goes to the database.As you can imagine not every single applicant is being looked at , its about who you know.
Be precise on your description, mentioned your experiences and knowledge, achievements. Have your patient thanked you and thought you are the wonderful nurse? You are a professional, show your skills, be confident and true.
Don't write something that you are not familiar with, be honest.
I got my ER job after having a clinical rotation during my rn refresher course(i have been out of work for 7 years), during my only 2 days of clinical I went to my instructor and asked her , how can I meet with a director or ER. ER director saw my friend and I during that time. We got an interview, but I was calling daily to follow up.