If you've ever attempted email prospecting in sales, you know the frustration of unopened or ignored emails. Before you start banging your head against the wall, take a moment to put yourself in the shoes of your customer. If you're reaching out to decision makers and economic buyers, then you're trying to catch the attention of someone who receives hundreds of emails every single day.

Your customers quickly skim their Inboxes to look for the messages that truly matter. They simply don't have enough time to open every email they receive. To catch the attention of your ideal customers so you can surpass your sales goals, try following these 5 simple steps to writing emails that even the busiest customers will open every single time:

1. Choose your subject line and first sentence carefully.

Since your customers don't have time to open all the emails they receive, they make the first round of cuts based upon the subject line and first sentence. Why? That's all they can see when quickly scanning their Inbox. Choose a subject line and first sentence that's simple and to the point, and be sure to personalize them. If your subject lines are vague, or your first sentences are boilerplate, your sales prospecting emails will never succeed.

2. Don't sound salesy.

When you try to impress your customers with a carefully structured, formal email, you're dead on arrival. In today's business world, most emails are conversational and casual. Only salespeople still use formal language, so it immediately stands out as salesy. Drop the formality, and send a casual message that will actually connect with your customer on a personal level.

3. Do a bit of research.

If your customer even suspects that your email is part of a blast campaign, you'll be automatically ignored. While you don't need to spend hours writing a single email, a little bit of research helps to make each email specific to a given customer. Just inserting their first name isn't enough--try including their company name, and then make reference to an issue or accomplishment specific to their organization. Showing you care enough to do a little bit of homework will go a long way.

4. Keep it short and sweet.

Your only goal in a prospecting email is to elicit a response. This is not the time to educate your customer on your offering, or to try to come across as an expert to your customer. Even if you send valuable information, the sheer size of a multi-paragraph email will overwhelm customers. You may catch their attention at first, but they'll quickly move on to other emails--and they certainly won't come back to read it again and respond. The most successful sales emails are 5 or 6 sentences at most.

5. End with a question.

One of the biggest prospecting email mistakes is ending the email with a close-ended statement like, "Let me know if there's anything I can do to help," or "Let me know if you'd like to schedule a phone call." This doesn't engage the customer or elicit a response. Instead, try asking, "Did any of these questions ring true to you?" or "What's the best address I can send this to?" Choose a question that customers can quickly and easily answer. All you need is a short response to get your foot in the door and continue the conversation.

Which of these simple steps have you failed to follow in writing prospecting emails? What changes will you make in the future to better engage your customers? Share what you've learned in the comments below.