Make sure that each sentence flows logically. The traditional way to do this when writing an essay is to use connecting words or phrases, often conjunctions (linking words) such as "although", "because", "so", "moreover", or "therefore". In this way, you build your logic and arguments. These connections come in simple and complex forms.
Although we sometimes need words to show the logic and connection between sentences and paragraphs, many connecting words make your style more complex and academic than necessary.
Use the connections to make sure your reader can follow the flow of information, ideas and arguments within sentences, from sentence to sentence and between paragraphs. But don't let too many connections creep into your writing and keep to the simple ones recommended.