If a nurse offers to be your preceptor and you would like him/her to be that preceptor:
1) Have them inform their nurse manager in writing -- a one line email or whatever THEIR internal process is
2) When they have done that then you give their name, position, location telephone number and email to the person that assigns preceptor positions.
3) Follow up, follow up, follow up
OR Find out who chooses the positions and ask them specifically what you can do to get the preceptor choice you want. Find out who is in the ED now being precepted and ask how they got it.
Your school may not choose to work with that person. At my school they like to choose nurses that went to our school or are known to the faculty. If you think about it you will understand why.
When competing for a space you certainly could write a note to the person assigning preceptors. Just make sure it is genuine and respectful. Follow up -- by going to their office during office hours (don't just email them).
By the way, I got exactly the preceptor placement I wanted. It happens I also have really good grades and work like crazy in nursing school
. So I think that helps.