The essay has a very important place in almost all the language exams in the world. It is considered an effective criterion of a student's intelligence and ability, and candidates taking the TOEFL (Test of English as a Foreign Language) should keep that in mind.
The most important component of any essay is, however trite it may sound, good English. As they say, language is a tool to express thought, and if your vocabulary is poor, you won't be able to make a proper impression on those who will test your work.

To write an essay that will get a high score from the examiners, you need a high level of English, and memorizing the rules of grammar or word lists is not enough for that. Your goal is to speak and write English fluently and confidently. Is assignment geek legit? And for that, read as much as you can in English. In fact, books, magazines, and websites are not only a treasure trove of useful words and phrases, but they also provide food for thought and inspiration for original ideas.

Each candidate who has to write a TOEFL essay has his or her own style. One writes with humor, another leans toward philosophy, and another looks for political overtones everywhere. The best way to hone your skills is to write at least one text every day, especially if your opuses are checked by your teacher, highlighting grammatical and lexical errors separately.

Keep in mind that the days when florid writing style was valued are long gone; now it's more likely to be smiled at than admired. Candidates should write naturally, clearly, and unsophisticated. Their essays should be characterized by simplicity of language, clarity of thought, and power of expression. Keep this in mind as you prepare for the TOEFL writing section, and good luck on the exam!

Related Resources:

What is an essay?
How to write an essay?
Problems and possible difficulties in writing essays
Essay outline (structure)