Unfortunately for most of us, our first exposure to writing was for grade school term papers or essays. I don't know about you, but I always did those things the night before, and rarely read them once they were written, let alone revised them. My job was to write, my teacher's job was to read, and no one revised. Once you get the idea that you will keep working on a paper, writing and rewriting it, until all the writing is good, the rest is relatively easy. Scrutinize each paragraph and revise it until it is a good one.
Topic sentences are particularly helpful and important.
Try to have one main idea for each paragraph. Paragraphs are good when they say what you want to say, and when all the sentences hang together harmoniously. When you are reading and rewriting your paragraphs, read them out loud occasionally to get a feel for their rhythm. Make sure that the paragraphs fit together nicely. Scrutinize each sentence and rewrite it until it is a good one.