First of all write down quickly your ideas about the topic (brainstorming).

Order them into advantages and disadvantages (or for and against).

Write a draft:

first paragraph: introduce the topic

second paragraph: advantages (supported by examples and facts) and disadvantages (idem)

third paragraph: state your opinion (closing paragraph)

Read it, check the connectors, the punctuation and spelling, revise the grammar and the word order.

Write the final essay on the computer and send it or post it.