Instead of accusing or reprimanding your reader, why not tell him what you need from him or what you want him to do? How might these be restated?
You failed to follow the application instructions; therefore, we cannot comply with your request.
You neglected to specify . . . .
You overlooked enclosing . . . .
Count the number of negative words. How might you rephrase these positively?
Instead of flattering the reader (usually not perceived as very sincere), how might you sincerely praise his efforts? Our company considers it a great privilege to offer you, the leading manufacturer of widgets in this region. . . (blah!) Instead:
Your detailed analysis of the problem seems right on the mark.
I especially appreciate the time and effort you spent showing me your facilities.
Use active voice to
Express appreciation or praise. Thanks! I really appreciate your help in determining the best way to finance our home.
State requests. May I keep a copy of your letter for my files?
Admit fault and/or apologize. I apologize for the grading error on your last assignment. I apparently miscalculated the score.
Deliver good news. Guess what? You have won our drawing for two complimentary tickets to the upcoming A&M/UT football game.
Use passive voice (or an affirmative statement) to
Soften criticism. The plants should be watered every day during the hot summer months. OR Watering the plants daily during the summer months will help them tolerate the heat.
Deliver bad news. Because we need someone who can assume the management position with minimal training, we selected an applicant with ten years of managerial experience. OR An applicant with ten years of experience was selected to fill the managerial position at Ameribank.