If there is more than one grammar mistake in each chapter of your books, then you probably won't get a review on it for bad grammar.
I'm trying to figure out what you mean here. If you mean that fics with bad grammar won't get any reviews
at all, then I'd like to let you know that ironically enough, on forum-based writing communities, fics with bad grammar are usually the ones that get reviewed
more often than fics that are clean. This is because everyone tends to jump at the chance to point out those kinds of errors, whether it's to show others that they know what they're doing or because it's harder to come up with something to say for a fic that has nothing wrong with it. Sure, you can point out the things you enjoy in the latter type of fic, but it's really easier to criticize than praise.
If you meant people won't notice
at all if you have bad grammar and a good storyline... that's unfortunately not true. Think of a story like a road, and readers are people driving on it. Each mistake is a pothole. Having only a couple in the road can be easily shrugged off, but if you have a lot of them, the drivers stop focusing on the pretty scenery around the road and start focusing only on the potholes. Even if that road goes through the prettiest countryside you can think of, it's suddenly not enjoyable because there's just too many bumps.
Of course, this has nothing to do with how an author can be more descriptive except to say that grammar is a vital part of a reader's ability to enjoy the work either way. (And even then, there's only a vague connection.)
To answer your question, xelarator, the best method is not only to think about what moves
you but also think about what would move
everyone else. Not everything that affects you would affect us the same way. For example, I once read a fic where the author thought having us watch a character mercilessly beat up a bunch of bullies with gratuitous violence to the point of nearly killing them would make us feel sorry for that character. Obviously, it didn't. Instead, a lot of that author's reviewers thought it was absolutely horrifying for all the wrong reasons.
Moving an audience is one part empathy. In order to figure out what would work for us, think hard about the things you have your characters do. Actions are the backbone of your description. If you have a character try their hardest to show her bullies up but fail miserably and only embarrass herself further, that would make us feel sorry for her more than having her beat the crap out of them. The reason why is because we can connect to that character; we can see her try her hardest but fail, despite how hard we're rooting for her. In the meantime, the description part of it is just a matter of building up the scene so that you coax us to root for her (perhaps by making it look like she might win) and then emphasizing her failure and the consequences.
In other words, moving the audience is just a matter of knowing what triggers what emotions. If you have a warm and fuzzy scene, figure out what people think is warm and fuzzy. One way to do this is by looking at other media. Look at romance flicks and see what kinds of elements they have in common or what kinds of things the people who watch them notice the most about the characters' relationships with each other. Look at angstfics and see what readers pick out as the most heartbreaking. Delve a little into the genre you're trying to write (for the moment) to understand how people react to different aspects of fiction. Once you figure out how people react to one thing or another, you can figure out what kinds of things you can put in your own work to create the same reaction.
But mostly, yeah, think hard about the things your characters do, and the description will come as support to that.
