The best way to do this is by using a transition sentence. While there are several ways to do this, I can share with you how I usually go about it. When writing an essay, before I do anything, I always look at how I am going to connect each body paragraph together. Cohesion between paragraphs is imperative to have a successful essay. Once you have these ideas, you now have the basis for your transition sentences. Once you have concluded with your thought for one body paragraph, this is where you would want to insert your transition sentence. Remember what your next paragraph is about and then write a sentence that connects your current point to the next point. Being able to transition between body paragraphs is a really great way to keep the attention of the reader and also to clarify your topic.
The way I do it - after I am done with my essay, I go back and re-read it paragraph by paragraph to see whether they are connected in any way and whether the argument in each paragraph is linked to one another. If some paragraphs seem to have absolutely different ideas and seem choppy, I try to fit in a transitional phrase or sentence to ensure a better flow for the overall argument of the essay.