Email has long been a cornerstone of business marketing strategy, especially in the information technology industry.

In fact, businesses say email marketing is critical in lead generation, according to a report from Demandwave, a B2B digital marketing agency. Its recent report on the state of B2B digital marketing found that 73 percent of businesses surveyed said email is the chief driver of sales leads, with search engine optimization right behind at 70 percent.

And capturing leads is important enough for marketing organizations that 85 percent of businesses have email "nurture" programs for leads, with half of that group calling their programs effective, and just 20 percent saying they're not. (The remaining 30 percent said they were not sure.)

Demandwave also found that 40 percent of businesses surveyed planned to increase their budgets for email this year. (There were higher percentages for organic search and social media.)

And when it comes to gauging effectiveness, email is an easy target since you can find out how many opened an email, how many clicked links, and what links they clicked on. Those are key digital metrics for Mandy Glidewell, director of marketing at Adapture, an Atlanta-based IT services provider.

"I like to look at weighted averages for email opens and clicks," she said in an emailed response to a question from ITBestOfBreed. "Even though percentages are a good and an important indication of the quality of your content and lists, I also like focusing on the actual number of people who opened or clicked on a message."

Open rates, click rates and links clicked most often are "important as percentages of your send or delivery volumes," added Gail Blount, an independent marketing consultant in Fort Lauderdale, Fla., who has worked as a marketing executive for a solution provider.

Do you want your business to get better at email marketing? Here are links to three recent articles that could steer you in the right direction.

BUSINESS 2 COMMUNITY: 7 ways to maximize the power of your B2B email marketing

Karen Taylor creates seven buckets by which you can categorize your emails and help accomplish your company's objectives.

CMS CRITIC: 4 tips for boosting your email marketing strategy

Want to boost your open and click-through rates? Alexia P. Bullard offers these ideas: Implement effective opt-in options, optimize for mobile devices, add video, and make sure your website design is effective.

MARKETING LAND: 6 tips to get subscribers to open marketing emails

Marketing executive Scott Heimes has more tips to offer, from creative subject lines to winnowing your subscriber lists.