Even if social media has been taking over the Internet, e-mail is still an effective tool for businesses to reach out to their target customers. Startups looking to beef up their digital marketing campaigns should avoid these five e-mail marketing flaws:

1. Ignoring double opt-in e-mail marketing

Single opt-in and double opt-in sign-up methods differ in the number of times people need to confirm their desire to be added to an e-mail list.

When single opt-in is used, people just have to submit their e-mail address once. They are automatically added to the e-mail list without confirming their subscription. In contrast, the double opt-in process sends a confirmation e-mail where users must click on a button or a link to confirm that they want to be added to the e-mail list.

Both processes have their own pros and cons, but settling for the single opt-in process could cause some problems for your business campaigns. While single opt-in helps build a large e-mail list, e-mails risk being flagged as spam or ignored by recipients, resulting in lower open rates.

Double opt-in e-mail marketing techniques lead to better results compared to single opt-in because the subscribers are more likely to be engaged.

Below is an example of how clothing retailer GAP Philippines uses double opt-in to ensure that its subscribers are really interested in receiving e-mail offers.

2. Weak subject lines

Subject lines are the first things people see when they check their e-mails. The subject line should be enticing enough for people to open the e-mail.

With so many messages vying for a user’s attention, how can a company make its subscribers want to open its e-mails?

First, a subject line has to make readers feel that the e-mail is personally relevant to them and that they will benefit from it. If a subject line clearly communicates the benefits of checking the e-mail’s content, a user will be more tempted to do so.

Personalization is equally important in crafting good subject lines. E-mails with personalized subject lines are 37 percent more likely to be opened than non-personalized e-mails. It can be as simple as including the recipient’s name.

Note the difference between these subject lines:

– “Get 40% off when you book now!”

– “Hi Sam, book now and get 40% off!”

DigitalMarketer, an online community for online marketing professionals, amps up its e-mail personalization by adding Unicode characters to its subject lines. This technique has helped the company get three times higher open rates.

Creating a sense of urgency (e.g., “Get it before it’s gone!” and “Exclusive limited time offer”) is also a good personalization technique for crafting e-mail subject lines. Website builder Wix.comused a subject line that told readers they got only 24 hours to avail its offer.

Lastly, subject lines have to keep a friendly tone. E-mail subject lines that are too aggressive, such as those in all caps and multiple exclamation points, can easily turn readers off.

3. Lack of automation in e-mail marketing campaigns

Marketers nowadays see the value of automation in their e-mail marketing campaigns.

In the 2017 E-mail Marketing Industry Census, more digital marketers said they succeeded in implementing automated e-mail marketing campaigns (from 62 percent in 2016 to 67 percent in 2017). Furthermore, 66 percent of marketers chose marketing automation as the top feature of an e-mail service provider’s technology.

To get higher open rates and click-through rates, business start-ups should include automation in their e-mail marketing campaigns.

Marketing automation involves sending e-mails that are triggered by a purchase, a download, and other actions. For example, visitors who placed an item in a shopping cart but just left the site may trigger an e-mail reminding them to complete the purchase.

Anti-virus software company Bitdefender also sends out triggered e-mails to dormant customers, reminding them of their expired subscription and providing special offers to invite them to come back.

Automated or triggered e-mails are timely and highly relevant to subscribers. ContactMonkey, a start-up e-mail tracking service provider, created a series of events that triggered e-mails, ensuring that every customer receives the right message at the right time. The results? Happier customers and faster growth for the business.

4. Poor e-mail list management

Managing an e-mail list entails weeding out invalid e-mail addresses to keep the bounce rate low, sending e-mails to inactive subscribers, and other things to increase open rates and ensure that e-mails are delivered only to interested people.

Buzzfeed reached out to its inactive subscribers, identified the non-engaged ones, and removed them from its e-mail list through its re-engagement e-mail campaign. It sent an e-mail reminding the inactive recipients that they have not seen the newsletter in a while and why they should care about reading the content. The message came with a button for readers to click if they are still interested in receiving newsletters from Buzzfeed.

5. Not measuring e-mail marketing campaign results

Failure to measure an e-mail marketing campaign’s results is a missed opportunity for any startup business. It is important to know what worked and what did not so that successes will be continued and failures are avoided in future campaigns.

Some of the essential e-mail marketing metrics to measure include the unique open rate, click-through rate, conversion rate, and subject line styles that got the highest open rates.

Start-up companies need to regularly review their e-mail marketing campaigns to check for flaws that affect their e-mail open rates. This is just one of the ways to keep customers engaged and coming back to their business.

Gary Viray, is the founder and president at Propelrr, a full digital marketing agency based in the Philippines that highly focuses on performance marketing and brand equity building. You can follow him on Twitter @garyshack.