Are your email communications too informal? Are they also overly formal? Are you speaking in the right voice?
Email messages differ from typed letters in several ways. In a letter, you can't be "too" formal. Overly formal emails come off as awkward. What kind of voice should I use in my emails? — a little less formal than a letter. However, there must be a balance between being loose and being stiff.
The degree of formality required will, in part, depend on your company's attitude and culture. For instance, a hotel or bank won't be as formal as a florist shop.
Remember who will be reading the message as you write it. Know your target market.
When you are responding to a message, the task becomes simpler. The sender's tone is clearly apparent. Simply match that tone is all that is required.
When in doubt, go for a conversational yet professional tone. Use of contractions (I'll, We'll, He's, She's) is one simple approach to convey a conversational tone.
Pronouns are also permissible. Us often say "I, we, you" in conversation. Use these in emails, then. For instance, the phrase "It is advised..." sounds rather stilted. Try using "I advise..." instead.
Take care while using the "I" pronoun. Overusing them could be interpreted as egotistical. You don't want to come out as haughty. Try revising every other sentence if you find there are a lot of "I's" in the sentence. This will add variation and make that annoying personal pronoun less noticeable.
A fantastic method of communication is email. Just keep in mind that your messages shouldn't sound stilted and formal by adapting your previous typed-letter writing style. Email, however, DOES NOT give you permission to be careless. Emails that are most successful strike a favorable balance. They speak in a casual manner.