Before diving into finding professionals to help editing your work, where do you find people who are willing to read your first drafts and give feedback and beta-read? And how do you know you can trust the person?
Right here is a good place to start. After 14 days of membership and 20 posts you are eligible to post in the collaboration forum and solicit beta readers there. Of course, it is expected that you will do the same for your beta-readers most of the time, so be prepared to critique 5 or 6 things if you seek that many readers. As for trust, well, how do you trust anybody about anything? Best bet is to find readers of your genre, as they will be your target audience upon publication.
When doing critique or beta swaps, I've always found it is helpful to swap just the first chapter or two, that way you can make sure that you enjoy the other persons writing and find their style of feedback helpful. You might still have some swap partners back out, but the feeling of mutual debt will keep most people invested and trying their best. Like Homer mentioned, we have a swap section here, but if you don't have much luck there, there are dedicated critique sites such as Scribophile which have worked well for me in the past. The Nanowrimo forums also have a pretty robust critique swap area. If you aren't doing swaps, you'll probably want to have multiple betas at a time. Some will just never get back to you, some will give terrible advice, some will have good instincts but no idea how to turn that into helpful feedback, but if you have several who enjoy reading your genre, chances are you'll find some gems. Once you find a good beta, you can try to cultivate a relationship and hold onto them for future books. It helps to start asking for non-swap or non-paid betas with a polished draft: the cleaner and more enjoyable a read is, the easier it will be to get people to read your book without giving them something in return (or rather, the free good book is the payment). I know people who have had luck finding non-swap betas through writing and reading-related social media groups and in person. You can ask friends and family members to beta read IF they enjoy reading your genre AND you believe that they will be honest and not dance around hurting your feelings. Even then, take friend and family reviews with a grain of salt until proven unbiased.
I'm pretty new to all this, but I found my beta through instagram. I set up my proflie about a year ago and have been posting about my writing journey and book reviews so I put out a call for betas and Ive used 8 of them so far. Its a good way of getting a mixture of viewpoints as some of them are fellow writers, others are readers and reviewers of my genre. Hope that helps!
