Writing competitions are an excellent way for new authors to not only get some name exposure, but also win prizes which will also help your writing. Be wary of ones that are vague or charge a lot.
Research the contest givers. A large association such as Romance Writer’s of America or the Arthur Ellis Award in Canada (which our John J won last year for best unpublished author) are legit. If the contest has been ongoing for a while and does not require you to buy your book — a poetry scam was active a few years back which basically took every poem sent in and told people they were specially selected, now buy this monstrous overpriced book. Avoid those.