That idea is introduced in a topic sentence. The topic sentence should generally lead on from the previous paragraph and introduce the point to be made in this paragraph. Transition words can be used to create clear connections between sentences.
There are many types of essays you might write as a student. The content and length of an essay depends on your level, subject of study, and course requirements. However, most essays at university level are argumentative: they aim to persuade the reader of a particular position or perspective on a topic.
For this reason, it can be helpful to simulate the conditions of a timed exam before the actual day: pick a practice question, find some lined paper, set a stopwatch, and see how you do!
The first sentence of the introduction should pique your reader`s interest and curiosity. This sentence is sometimes called the hook. It might be an intriguing question, a surprising fact, or a bold statement emphasizing the relevance of the topic.
Define a topic: If you`re allowed to choose your own topic, try to pick something that you already know a bit about and that will hold your interest.
If you did your best to write a complete, clear, and insightful essay within the time allotted, you should have nothing to worry about.