I would never trust another person with my eyebrows!
I find the easiest way is to draw on the shape as you want to see it with a good eyebrow pencil, and then pluck around the shape you have created
An interesting (slightly insulting, with diagrams!) article here:
vice[dot]com/en_uk/read/pretty-girl-bullshit-the-bikini-line-myth
What are your experiences?