The 'key ingredient' in email marketing is a quality email list – 'quality' is the operative word.
This means a list of emails you've gathered by launching a marketing campaign with specific topics, usually through a reputable email marketing service (such as GetProcess or Aweber).
In other words, these are a list of people you know who are really interested in specific topics in your campaigns.
You can search online as there are so many companies like Email Data Pro which provides you information about online email marketing.
Image Source: Google
Conversely, quality email lists are usually not the ones you can buy online. Why not? Okay, can you really trust the person telling you that the emails they are selling to you are really interested in people like that? Gardening or any other subject you are involved in?
Other email lists purchased do not work, are you the people to contact with these lists, do not understand you personally, are not expecting to hear from you, you personally, to contact them Has not agreed and similarly you might not realize, you hope, or even click on their email (if it reaches their inbox and does not exit the increasingly successful spam sensor). Also, what you are doing is known as 'spamming' and, guesses what, it's illegal!
To create a more general-purpose, which also applies here, in online marketing you want to understand as much about your audience as you can. You have to get a perception about what they need, what part of the planet they live in, etc.
Two email addresses can inform two individuals from different regions of the world with huge socioeconomic differences and purchasing capabilities, different age groups, etc. Wouldn't you need to know which email matches that?
For example, the toy business, a multi-billion-dollar industry, spends great resources to determine how to promote an area of the population that has zero purchasing power (children). And they won by developing innovative methods to drop children and target their parents, just starting the so-called influence.