The fundamental idea is to give people something that aligns with the type of subscriber you seek. For example, if you wish to have a list of SciFi readers, a free SFF short story, book, or character dossier would be very appetizing to the sort of people you wish to attract. It can’t be something they can get from anywhere (like an Amazon gift card) but instead something genuine that you have created.
Open rate shows a percentage of total recipients that viewed your email. You can track it in HTML emails that include a transparent image (a tracking pixel). When it’s loaded, an email is tracked as open. This metric isn’t 100% accurate. As mentioned earlier, some email providers block images, and a user needs to enable them to see the visual elements.
On the flip side, Aweber’s method of managing followup emails allows me to know exactly which subscriber has received which follow up emails and when. With MailChimp, I really have no clue who has or hasn’t received a particular email. Overall, I kind of prefer Aweber’s method of managing follow-ups but it is basically a wash depending on your preference.
Never send an email without making sure it’s working properly. What looks good in your inbox can look broken or mangled in someone else’s. Use tools that can help you with testing your SPAM score, deliverability and the rendering of your email. There are plenty of free or freemium solutions that provide screenshots of your email in dozens of different email platforms.

Finally, you can optionally include “automations” with your broadcast. Automations are a simple way to automatically add or remove tags when your subscribers do certain actions, like open the email or click on specific links. Adding and removing tags are important when creating segments, or subscriber groups, and triggering automated email campaigns.