Particularly the idea of -ed vs -ing and -ed vs -sBut what about them! What is so important about prefixes and suffixes, especially these two? That was what I wanted to know! Apparently a great deal! A common grammatical error that writers stand to make on a regular bases is forgetting their verb tense. It is not something that many people - I know I don't - think about, because it just does not feel natural. However, for writing, natural isn't always how one goes and gets published.
So what can you do?
Stay consistent! This very easy idea is actually very hard to execute when writing. I myself have gone through several of my previous texts in order to check my own consistency. I will spare you the pain of such an experience. How can you remain consistent? Make sure that if you have a paragraph/page/book that uses the -ed verb tense, keep it that way! Or if you have a paragraph/page/book that uses the -ing verb tense, stay consistent. This one little rule may surprise you in how often it is misused.
Keep in mind this does directly correlate to past, present, or future tense, and as that can change in a paragraph, well, so will your verb tense. Let's make it more complicated!
Let me give you an example so this is easier to grasp. This is a short excerpt from my own short story, "Shoes". Lo and behold I made this mistake more than fifty times in the first draft.
ex 1)"..."Chatty?" he asked, looking down at his older partner..."
ex 2)"..."Chatty?" he asked as he looked down at his older partner."See the difference there? That small edit changed the entire tone of the sentence, and created consistency, whereas the other sentence led me into a five comma run on!
This is just a brief look at this rule, but for more on verb tense, I have provided a link below that discusses the real nitty gritty of the rule!