How to publish a book p.s still writing it?

i am writing a book and want to get it published i am thirteen and i know that it will be hard i just want to know if you have any tips on writing and how much a editor will cost also it is a YA ( young adult) book my book is about a girl who's sister is murdered and tries to find the killer also do you know if you touch a dead body as in hold it will you be considered a suspect