If you study in high-school or university you should be able to write effectively. If you want to write about something specific one of the best ways of doing it is to ask a question. By asking a question it gives you a clear picture in your head of what you want to know. By asking a question there has to be an answer. The reader wants an answer to this question. By asking a question it helps to get very specific in your focus. There should be a focus on your target.
Writing an effective essay includes several parts:
1. Writing a question.
When you figure out the answer to the question, write it down. But it’s not just an answer, in English it becomes your thesis. The thesis is what you should focus on. That's why you should ask a question.
It is the answer to your question. Your thesis should be strongly and clearly stated. You can't say "maybe", maybe yes or maybe no. It's not a thesis.
In the introduction you add your thesis to some nice words to introduce it. People reading an essay should be able to identify your thesis.
4. The Body
In the body you should prove your thesis. You should have at least three main reasons (ideas) that make the thesis true. You should also look for other things that will support these main ideas.
In the conclusion you should go back to your three main ideas and since each one of them is true the conclusion must be true.
If you follow the above steps you will become an effective writer.