If you love picking out and sending just the right card for every occasion, and if you're a whiz at designing that perfect card yourself, then niche greetings cards is the business for you.

Figuring out how to start an email - especially when you're writing to someone you don't know very well - can be a real challenge. Is "Hey" too casual? Is "Dear" overly formal? Is "Morning!

"Many people have strong feelings about what you do to their names and how you address them," Barbara Pachter, a business-etiquette ... on a handful of common email greetings.