Resources for Authors
Pro Writing Aid is one of the best tools out there for authors, and one that I cannot recommend enough. I have been using it for some time and my writing has improved immensely. They have several plug-ins aside from their main editor that I suggest taking a look at.
See how to maximize Pro Writing Aid as an author in this tutorial.
I don't think I've found an easy, more straightforward grammar checker for beginners than Grammarly. While it isn't perfect by any means (what machine is?), it's simplicity and unclutters interface is excellent for authors just starting out. And its free version covers all the basics you need to help you produce a cleaner first draft.
You can check out my full review of Pro Writing Aid vs Grammarly on my YouTube channel to see for yourself which will be a better fit.