Picking a great subject line for your email campaigns is a lot like playing roulette – sometimes, without A/B testing campaigns, it’s impossible to know where your efforts will land. But with email marketing playing a major role in the short and long-term success of your business, it’s imperative that you take steps to ensure you’re sending out awesome subject lines that won’t alienate your readers.

According to studies, the two most important factors to determine whether an email is opened are the sender (64%) and the subject line (47%). If that’s not impressive, take into consideration that 35% of recipients open emails based on the subject line alone.

A single line of text can have a major impact on the effectiveness and outcome of your email marketing campaign. If you’re looking to increase your open-rates and drive sales to your online store, take into consideration the following do’s and don’ts of subject lines.

1. Avoid spam triggered words

Certain keywords have a tendency to trigger spam filters and/or cause recipients to quickly mark your mail as junk. According to email marketing service MailChimp, words commonly triggered by spam filters include “help,” “percent off,” and “reminder.” Try and avoid these common sales-pitchy words if possible. You’ll also want to tone down your sales pitches by refraining from ill-received punctuation such as all caps and an overuse of exclamation points.

2. Add urgency by including a deadline

Create a sense of exclusivity by including a deadline in your subject line. Shoppers are always on the lookout for hot deals that promise great bang for their buck, and are more likely to open your email if a sense of urgency is established. Let customers know that your limited-time deal is just that – limited, and push customers to take action sooner rather than later.

3. Keep your subject lines short and sweet

Email recipients browse their mail in a hurry, scrolling through countless advertisements that continually promise timeworn, hackneyed deals. Ensure your email doesn’t drown in a sea of trite clones with a short yet captivating subject that’ll draw eyeballs like moths to a flame.

4. Pose a question

Your email recipients are inundated with countless promotional emails that for the most part, pretty much all look the same. Nearly everyone advertises Labor Day, Black Friday, and Cyber Monday deals. And while these are great days to market your store, your subject line doesn’t need to follow the masses.

Shoppers are curious by nature, and nothing will get their attention faster than a subject that poses a question. Just remember that your body needs to provide the answer; don’t leave your shoppers hanging with more questions than answers.

5. Personalize your message

Everyone loves to feel special, even in the eyes of their favorite brand. Your email campaigns are sent to hundreds and thousands of individuals, but that doesn’t mean you can’t personalize your message. Including your recipient’s name in the subject line is a proven tactic for increasing open-rates. People love to see their name, and are more likely to find your content of interest when they believe it’s tailored to their interests or benefit.

6. Make your subject lines mobile-friendly

Billions of people use their mobile devices to check their email at school, work and nearly everywhere on the go. This tip goes hand in hand with keeping your subject lines short and sweet. While longer openings may seem more appealing, especially when you’re desperate to pack a bunch of info in a short space, it’s important to remember how this will appear to mobile viewers. Keep in mind how and where shoppers are reading their mail and always optimize your subject lines accordingly.

7. Switch up your subject lines

Your last 5 email campaigns may have all been related to a 25% discount or free shipping, but that doesn’t mean you need to use the same subject line over and over. Every piece of produced content from your business should always be new and fresh. Recycling your words will decrease the value of your perceived deals, and may cause shoppers to quickly lose interest with a business that’s stuck on repeat.