Complete your essay before you consider the title. This is because you might otherwise make changes to the body of the essay that would no longer be well represented by a title you picked too early in the process.
Look through the completed essay to find ideas for the title. Often in the introduction or the conclusion you can find something that might work. Write down several possibilities.
Choose a formal, serious title if the essay is on a serious topic being given to a professor or a journal. If however, you are send the essay to an online publisher of popular teen content, you will need something edgier.
Avoid complex terms of technical jargon in the title. Save that for the body of the essay.
Make the title four to five words long. Longer titles are often overwhelming and shorter titles can be too vague.