For me, editing fiction is more interesting because it’s part of the creative process. But wether it’s fiction or non fiction editing can be rewarding. Sometimes, I find, it’s best to revisit a piece after a day or two after completing. When you return and reread, often it’s that little break that helps you see where you may need or want to make changes.
Also, it’s always helpful to ask someone else to read what you’ve written prior to editing. It’s allows you to get feedback from a different perspective. Most importantly, don’t be afraid of constructive criticism, I find it very helpful to hear what I need to work on, it makes me a better writer.
I think the better questions is what is YOUR favorite type of editing, and why. I've edited many genres at various stages, and I've found that there's plenty to love across all of these, and so I'm going to treat this question as "how do I find the best thing for me."
That said, a good way to figure out where you want to be is to think about what feels natural to you, and to branch out into other things and really pay attention to how it makes you feel. When I was in high school, I loved reading and writing fiction; unsurprisingly, I loved editing it, too. I began my career at the start of the Great Recession, and that meant that to stay in the industry I had to do a lot of different things. This ended up being good for me, because I tried things I never would have--college level textbooks, medical publishing, business books, children's books, etc. It also meant I got to try my hand at acquiring (getting new projects), writing articles (though I did only a little of that), development editing, copyediting, proposal writing, technical writing, and proofreading. With such a broad history, I was able to figure out what roles I wanted to be in and in what genre, and it gave me enough experience to do a wide range of things. Many book publishers don't allow this, so it's truly special that I was able to jump around. Without that broad history, this would not have been possible. I would have been like many book editors--stuck in one thing. That might have been fine, but I would not have ever been sure of what I wanted most, and I would have always wondered as a result.
That said, the best thing to do is be open-minded and try your hand at every kind of opportunity you can get. Sometimes, this is easy; high school and college newspapers are a good start. Many blogs and other such publications are always looking for unpaid editors, which is a good thing if you're still in school. If you can get a writing center job, do it. Basically, if someone is willing to let you try something, take them up on it to see what you learn and how you like it. It can be a lot of work. Sometimes, it's a little demoralizing, and sometimes, it's fun. But one thing is certain: you'll always surprise yourself, and you'll come out with a better understanding of who you are and what you can do.
I also love that you're asking these thoughtful questions so early on in your adventure. Keep doing that! Find anyone and any community where you can do that, and take advantage of it as much as possible.
Nadina recommends the following next steps:
I find editing nonfiction and technical material much easier because the styles in these kinds of writing tend to be more rigid. Though long-form journalism and creative nonfiction can certainly provide many exceptions to this rigidity, editing material that provides for less creative license is generally easier, though it might be less interesting or rewarding, depending on the kind of experience you're looking for. Creative material, and particularly fiction, in which the author is literally creating a world out of her or his imagination, allows an infinite number of possible intentions, conventions, and creative directions, so editing this type of material can take you into the futility of trying to read an author's mind. You of course address this by talking to the author to better understand their intent, but this can be challenging, and the roles of editor and collaborator often become blurred, which can make the editing process uncomfortable. Having said all that, there are many authors who want just that kind of relationship with an editor, and many of these collaborations are hugely successful over long periods of time. For me, though--and particularly if you're just starting out--the clarity and discipline of editing less creative material is more efficient and more rewarding, and requires less time, effort, and emotional investment. In addition, I believe editing nonfiction and technical material is more lucrative, though I haven't made an exhaustive study of that.
Bruce recommends the following next steps: