There might be two situations that will force you select a topic for your essay: one is when you really do not feel like working on any topic from the given list, and another one is when there is no given list at all. What to do? Where to start? How to make a choice and get the ideas?
Step 1: What?
Try to start with brainstorming some ideas. It will be much easier if you can limit yourself to a certain period, phenomenon, person or term. This limitation will let you search for the interesting info online without distraction, as in case the number of problems you are going to make a research about is too big, you will shortly be drowned in the information flow. For example, you have to write an essay about the beginning of World War II. Ask yourself questions: Is there anyone worthy to know more about? What is the aspect you would like to talk about, the reasons of the war, description and analysis of one particular event or person's actions or what happened right before it? Think about it, search more about it, and you will soon find your perfect topic.
Step 2: Why?
Take some time to estimate the type of the essay and determine the goal you strive to achieve with it. For instance, you decided to write about happiness. Do you want it to be a descriptive essay? If yes, then concentrate on the happiest day of your life (real or fictional) and on the way you perceive happiness. If you plan it to be a compare and contrast essay, you can write about what is similar and different between happiness and joy or satisfaction. For a persuasive essay, try to talk about how the concept of happiness differs from person to person and why there is no one common idea of happiness that everyone shares.
Step 3: How?
Indeed, how are you going to influence the reader? In case you want to impress your teacher with something they might not know yet, you can choose something extraordinary, like «What is the chance of robots taking oven humanity?» with a number of situations used as the evidence and to support your point. If you want them to really feel the essay and, maybe, be slightly overwhelmed with emotions after reading it, choose a topic like: «Human trafficking in a modern society».
Additional tip: If you have ever read a good example essay on your subject, you can use it as a source of inspiration and use its topic or a variant of its topic for the current essay you have to handle.
If you have noticed how much your history teacher talks about Napoleon, you can use it for your benefit and compose a paper about Napoleon, too. What is risky about it, you may ask? The answer is very simple: since your teacher knows a lot about him, there is a risk to use unreliable sources or support the idea your teacher considers to be incorrect or a result of a misunderstanding.
Check the Notes
Our memory is temporary; therefore, you cannot claim you remember everything about the subject. You can use your lecture notes to find your perfect topic. A simple look-though can help you refresh a memory about an interesting fact or event you would really like to know more about. Use this fact to be a shining guiding light of your essay and a point for being attentive.
However, any piece of advice regarding your topic is basing on two most important principles:
Interesting for You and Your Reader
We get the best pieces of work if we are fond of what we do, and it has been true since eternity. Any reader will feel if the creator was absorbed in work or have been working on the paper for three hours just to meet the deadline. However, academic writing is not art, so one should never forget about the reader, as well. The ideas should be clear; the topic you have selected should be followed until the end and make the reader feel like check the essay written on it.
And here is one more additional tip regarding this.
Imagine You Are Your Reader
Think about the essay you would like to read yourself and write it. If you take some time to remember what you have learned and what kind of additional materials to work with, the questions like “What topic do I choose this time?” will never bother you again.