I always tell my students that there are two things that they need to do in each body paragraph of an essay. First, they have to make sure that they are providing evidence that supports their thesis. Second, they have to write the paragraph as if it were a mini-essay on its own.
Taking the second point first, each body paragraph needs to be like a short essay. It needs to have a thesis/topic sentence that tells what it is about. This is like the introduction to an essay, only shorter. A really good thesis/topic would include a transition that links it to the last paragraph as well. The paragraph then needs to have a "body" of its own in which you provide evidence to add detail to your topic sentence. Each of the sentences in the "body" must support the topic. Do not put in sentences that are not on that particular subject. Finally, the paragraph should have a brief conclusion. It needs a sentence that wraps it up and connects it explicitly to the thesis of the overall paper.
This brings us to the other thing I always tell students: your body paragraph must support the overall thesis of your paper. The previous paragraph tells you how to write the body paragraph, but it does not talk about what to write. A good body paragraph must always refer to the overall thesis of the essay. Its point is to prove the thesis. You must be sure as you write that the points you are making truly do support your overall thesis.
So, there are two aspects to a good body paragraph. It must be structured logically, like a mini-essay. In addition, it must have the right content, content that supports the theme of the essay as a whole.