Misleading subject line
According to the blog of the HubSpot company, the subject line of the e-mail should engage the prospect. So it should not be boring. But at the same time, it can't be misleading either: if you "lure" the addressee with a subject line that has nothing to do with the e-mail text itself, the prospect will most likely delete the message immediately.
Clichés
In both the subject line and the main text of the e-mail, you should avoid clichés that are typical of mass e-mails. So leave out such phrases as "unique opportunities", "limited offers" or "90% discounts".
Lack of knowledge about the company and its products
In your e-mail, you should make it clear to the addressee that you have done your research on them or the company. Your opening should neatly interconnect what you offer and what the prospect does. Beware of making big mistakes and do not make it obvious you haven't a clue what the given prospect actually does.
Too long a text
The rule nowadays is: the shorter the text the better. Many salespeople do not want to leave anything out and end up writing huge chunks of text. It also takes them a long time in the introduction to get to the point. Be brief, forceful and do not drive readers away with long texts.
Desperate tone
There is nothing worse than a salesperson who sounds desperate. Your message should be positive and motivate the prospect to become interested in your product. It definitely should not beg the prospect to pay attention.
-mm-