A successful email marketing strategy is equal parts art and science. I put together a list of 10 key things to keep in mind

1. Remember the end. Before you begin, keep in mind what you are trying to accomplish with your newsletter. Most of the time that is defined by who you are talking to and what you want them to do. By keeping your tactics in line with your goals you will make faster decisions and produce better content that will grow your list and deliver a higher return on your investment. Now let's get started...
2. Remind your customers you exist. Many new business opportunities happen as a matter of being in the right place at the right time. Through a regular newsletter you can help stack the deck in your favor, by always being "in the right place" when it is the "right time". Keeping yourself top of mind with your customers will remind them to think of you when they hear of an opportunity that would be a great fit for you.
3. Build a relationship, not just a pipeline. When you have an associate who gives you permission to send them information, make sure you don't badger them with blasé. Only 28% of those between ages 18 and 24 say the email they currently get from companies is relevant to them. You've got an opportunity to share insight, ideas and inspiration. Take a minute to remember why your audience signed up to hear from you in the first place. When you get this right, people won't just read your content, they'll share it.
4. Don't over do it. 59% of US and UK Internet Users said the reason for not regularly opening/reading email marketing messages is that they come too frequently. If you are constantly stretching to find content to fill your newsletter, then maybe you're trying too hard. Find a comfortable frequency that fits the flow of your business. This will also help to ensure that your content is relevant and useful without becoming easy to ignore.
5. Don't give away the cow. When you are organizing your content, keep in mind that you ultimately want to use the newsletter to bring people back to your website. Too many times people try to jam all of the news and content they have directly into the newsletter, which doesn't give anyone a reason to return to your site. Determine what the key content items are and then just give your readers a tease with links back to your site. With effective tracking you can begin to see a pattern of which content is most interesting to your audience as well.
6. Break the bottlenecks. What is keeping you from sending out a regular newsletter now? Most often there isn't a person who's job it is within the organization to make sure it happens. Secondly many companies struggle with the process of publishing the content to their websites. The number one reason companies don't use or test landing pages is because their marketing department doesn't know how to set them up or they are too overloaded. - MarketingSherpa "MarketingSherpa Landing Page Handbook (second edition)"
7. Know when to send. People will open and read email differently from day to day and even within a given timeframe. People are more receptive to marketing emails during the first hour of their work day. Pure360 reports 16.5% of emails in the study were opened between 9 a.m. and 10 a.m. and 42.6% of financial emails were opened after lunch, indicating that workers are more receptive to so-called bigger-picture or life-changing messages in the afternoon. Best day to send? Tuesday, just so you know.
8. How to say hello. Getting the subject line of your email may be the single most important decision you make. Seven in 10 US Internet users said they judged these "from" and "subject" lines when deciding whether to report an email as spam. Generally shorter subject lines perform better and including the company name in the subject line can increase open rates by up to 32% to 60% over a subject line without branding. As a rule of thumb try to keep the total characters in the subject to less than 50.
9. Deliverability is based on relationship first. Don't buy email lists. Don't buy email lists. Don't buy email lists. I almost want to say that again. If you want to use email effectively, make sure your audience wants to hear from you first. There's no faster way to waste money than to send an email no one wants. Use OPT-IN lists only. Give users an easy way to unsubscribe (which is mandatory to comply with CANSPAM laws), and subscribe. Content will keep them coming back and great content will have them forwarding you. Oh, and don't buy email lists.
10. Email is still the king of the social hill. 56% of US Internet users interact with brands only via marketing emails, compared to 1.3% who interact only via Twitter and 0.7% by Facebook. With all of the popularity and promotion happening around social media marketing, many companies overlook the value of a well thought out and well executed email marketing strategy. If done correctly email can far surpass the effectiveness of newer, trendier social media tools.