A recommendation from the late Gary Halbert, a copywriter who generated hundreds of millions in sales:
Don't just read good copy, COPY good copy instead. (Word for word)
It sounds ridiculous, I know.
But when you copy a good ad or sales page,
You're teaching yourself first hand and internalising what it takes to write a good piece of copy.
Later, you can try apply what you've learnt in your own pieces.
Hope this helps someone.