There's really only one way to learn writing, and you can't get around it. The way to learn writing is by writing.
It's not an easy point to get across. Everyone who wrote a valentine in fourth grade is convinced he knows how to write. So does everyone who's written a letter to her mother, a note to the gas company, or a business letter to a vendor. They're writers, right?
They've written, but they're not writers.
I remember a discussion I had with Don David, the copy director of the Detroit advertising agency I interned with the summer between my junior and senior years. Another intern had asked Don if he could now call himself a copywriter.
Don told him the story of the yacht owner who called himself "The Captain". One of the crew members said "I can call you a captain, and you can call yourself a captain. But the real question is, does a captain call you a captain?"
A writer has to write. Not want to write, or often writes, but has to write. Every day. Or he'll suffer the withdrawal symptom of becoming very irritable.
If you want to be a writer, you have to read. You have to know about everything. Psychology, philosophy, war and peace, popular culture. That's right, if you want to be a writer you have to read People magazine, the New Yorker, the Atlantic, and Scientific American.
You have to write constantly. If you want to be an advertising writer, you have to read ads and study commercials, movies, TV shows, plays, videos, and real life. Mostly real life. You have to listen to people; how they talk, and what they talk about.
Then you have to write ads and commercials even for clients you don't have. Tear an ad out of a magazine and rewrite it. Make it better; funnier, more human, more relevant, more sensitive, more insightful. More useful. Look at TV commercials with paper and pen in hand. Rewrite them, then and there.
I can teach you how to write, but I can't make you a writer. That part's up to you.