When you write thank you notes, write them by hand. You can never send too many of them, and it is a gesture that will be remembered. They need not be long and flowery; short and sincere is a very effective style.
Writing business letters is a skill in which most professional people need some polishing. The casual meandering of a personal letter is not appreciated in business. You can waste a person's time with your letters as easily as with a phone call. Get rid of those pat phrases at the beginning of a letter like "thank you for taking time out of your busy schedule to see me" or "it was a pleasure talking with you on the telephone yesterday," that have become trite with overuse. Let the person know you were really listening by starting your letter with a specific reference to something the person said or did. For instance, "Your comments about the IBM-Apple merger during our meeting this morning were certainly thought-provoking. I appreciate your frankness."
Another annoying phrase, "If you have any questions, please feel free to call and I'll be happy to answer them," appears at the end of too many letters. A simple, "please call if you have any questions or need more additional information," is cleaner and clearer.
My pet peeve in business correspondence is a particularly American habit of addressing someone by first name in the salutation and signing the letter with your full name. The rule is, if you address someone by first name, you sign with your first name or you're talking down to that person. If you're worried he or she won't know who you are, then you either haven't been specific enough in your letter or you don't know the person well enough to use first names. Anyway, your name should be typed in full under your signature in a business letter.
Business stationery is for business use; personal stationery is for personal use. If, because of your position you do a lot of community service work, the ideal solution is to have the business stationery printed with your name and the company address, but without the company name or logo.