Read everything published on: - www.conversion-rate-experts.com - https://copyhackers.com - Ramit Sethi (i learn a lot by assessing his messages)

Also, the most important thing I learned: do not rely on your intuition the best copy! Run a short open survey with your client and website visitors to learn what they want and how they describe it - then, use their exactly words and phrases and scenarios to describe the product