You don't need a degree in writing to be a writer; that one is for sure. However, you must have a specialization, as some writers focus on technology, others write about arts, while others cover lifestyle. Of course, the first qualification for a writer is your fluency in the language you are using. If you are writing in your mother tongue, then make sure you can organize and relay messages in writing clearly using your language. If you write in a second language, then make sure you have somehow mastered the basic grammar and writing rules of that language. Creativity and resourcefulness are also necessary for writing. Lastly, writers must be readers, so read a lot.