Choosing the right language
Whatever might be the reason for your subject line, the choice of language you intend using should be well constructed as this can be another make or breakpoint in your email setup. It is advisable to use words that motivate and at the same time what your potential reader can relate to. Create an image in the mind of the reader by using direct languages which are used for a call to action, there have been considered extremely effective. A catchy phrase like call now, download, will do the work.
Define Your Purpose
This is another aspect of email writing you must consider to maintain complete effectiveness, which is defining the purpose of the email even before writing it. You must stick to a mindset at a time, if all you want to do is get people to sign up then you will need to focus on this. Immediately you are done writing you should refer to your purpose to ensure that your writing is well on track. With this always on your mind, you will be sure of writing with guidelines instead of typing and trying to deviate from the original message.
Finally, you must remember that most of the internet traffic is gotten from mobile devices like smartphones and tablets so you must ensure you optimize your emails so they can be easily accessed from these platforms.
You said something that really drove home. What the writer must to to make the reader willing to open future Emails. Hence, it is not only necessary to help the reader make a decision for the email he is reading, but also to include a snippet of what to expect in the next Email. Like a cliff hanger at the end of a TV series for the season.
Great job here.
The only improvement I can think of is to give actual examples of a selection of Subject Line messages.
Some examples to illustrate the various sections of the Email would also be helpful.
Other than that, you provided the information necessary to write captivating Emails.
Thanks.
Edwin