Try a subject line such as "How to effortlessly erase those fine lines and wrinkles in less than 7 days." I know I'd be interested!
3) Pump up your subject line with words like "simple" and "easy". In example No. 2 I used the word "effortlessly" - people like effortless! If your email suggests that what you are sharing will make your readers' day easier and simpler - they're going to open it up. Combine power words with odd numbers and you've got a winner.
Some other great power words are: Discover, learn, secrets of, do you, how to, imagine, protect, facts about, you, the truth about, and results. "Discover 3 secrets to boosting your energy in 7 days."
Stay away from: Amazing, revolutionary, great, all new, (when just "new" would suffice), guaranteed, FREE, and even special and important. These words will most definitely dump your email into the recipients spam folder. "Revolutionary new program guaranteed to increase your income 100% in 30 days"! Whew - that's a spam email if I ever saw one!
Basically, you want to solve your readers' problem. If you keep that in mind, and follow the tips I just gave you, then struggling with subject lines should become a thing of the past.