I write poetry and make greeting cards. I would like to make cards with my own words to sell, and would like to know how to go about getting copyright, since one day I would like them published in a book.
Your poetry is your intellectual property, over which you have rights both before and after you market it. As long as you can prove that you wrote it you can take legal action to prevent anyone copying it, distributing it or selling it for commercial gain. In order to prove that you were the author, and to establish the date on which you wrote the poetry, you could lodge copies with your bank or solicitor. Failing that, post copies to yourself so that the envelope acquires a date stamp, and keep the sealed envelope somewhere safe.