The most basic component of email marketing is your list. This is the actual list of people and their email addresses that you’re going to send your messages to en masse.
First things first: do not buy email lists. If you forget everything else in this post, remember this. Do not purchase email lists! Buying lists is bad for so many reasons, not the least of which is the fact that you’re officially a spammer when you use a list you had to pay for.