IMPORTANT REMINDER: You are not permitted to ask a German speaker to proofread your essay. But it is OK if you ask someone 3 or 4 specific questions like "Is this phrase right? How do I do this?"
1. Above all, please don't write out an essay in English and then try to translate it into German. This will be an awful amount of work for you, and using a dictionary to try to do a lot of things you haven't learned just leads to lots of misunderstandings. Doing this often causes students who have worked very hard to get bad or mediocre grades, because the result is often incomprehensible.
2. What's easier
and much more fun is to try to put the essay together using the German you have
learned: write down relevant nouns and verbs first. Look up only what
you know you'll really need and want to use. Look up words you've found in the
german-English part to check that they mean what you think they do.
--then make very simple subject-verb-object sentences out of these verbs and
nouns.
--now see if you can add anything else you've learned: connect some of your
sentences using und, denn, sondern, aber, oder. Add some adjectives and
words like "manchmal" or "oft" or "leider."
--vary the word order in your sentences, i.e. put something other than the subject
in the first position of a few of your sentences. Remember the conjugated
verb always comes second, and the subject comes right after the verb if it is
not first.
3. Writing in this way will make you write better: the linguistic limitations can inspire you with fun ideas, and writing clearly and simply is the best way to write in any language.
In general, the more you can put your essay together in German, the better!