Transition words are an essential part of any high school essay. They add depth and help the reader to see the connections between sentences, paragraphs and ideas. Transition words can also provide emphasis and help create a logical flow in an essay. There are a wide variety of transition words that can be used in essays, and some of the most common include:

First, Second, Third: These words are used to organize a list of points or to provide a sequence of events.

Moreover, Furthermore, In addition: These words are typically used to introduce additional information or support for a point.

However, On the other hand: These words are used to contrast ideas or argue against a point.

Finally, Therefore: These words are used to summarize a point or come to a conclusion.

In conclusion: This transitional phrase is used to conclude an essay and provide a sense of closure.

Using transition words in an essay can help to establish connections between ideas and provide readers with a better understanding of the message being conveyed. By using a few simple transition words, essays can be transformed from choppy, disjointed messes into well-structured, flowing pieces of writing.