You should consider investigating and using one of the many email marketing providers available, sometimes referred to as communication software systems. Doing so with a program like Constant Contact (constantcontact.com) or MailChimp (mailchimp.com) will allow you to look professional and track who’s opening and reading your email. These programs also give you the opportunity to personalize each email with your customer’s name, company, and other important points.
With these mailing programs, you can easily use your brand or field of work identifiers to narrow down the recipients of a mailing so front-end technicians get front-end tools, etc. These mailing programs vary in pricing from free for the basics to $20 per month. Track who’s reading, run surveys, and resend mail to anyone who didn’t open the first time. These programs also fill all your legal needs by giving recipients the ability to opt-out any time they wish.
You may also want to watch one of the tutorials on this subject such as this one from Constant Contact.