Here are all of the released examples from the 2018 STAAR test. You can read the essay and read exactly why the essay was given a specific score.
It is helpful to see examples to help guide your writing. Do not try to memorize any of these essays or try to only follow that specific "formula". That will not help you if the prompt is completely different.
Read through some examples and think about the following:
What was the prompt?
What was the author's answer to the prompt? (This is their THESIS STATEMENT)
Did the author provide any reasons?
Did the author provide any examples?
What kind of examples did the author use?
How did the author organize their writing?
If you review essays that scored a 3 or a 4 and considered those 6 questions, you will notice a pattern. High scoring essays do use reasons and examples. High scoring essays are organized in a logical way. Look at the types of examples that are used and consider how you could think of similar examples! Once you feel confident that you know what a good essay looks like, feel free to continue on!