This is different to the purpose of a meme. The difference is important because its about picking the right tool for the job - hence links back to strategy (the actual strategy bit - i.e. the why, not the how). Its the meme vs. advertisement discussion.
A meme is basically a self replicating piece of information. It does this by triggering a response in the human viewing / reading it to make them propogate it to other people. This is the basis of something "going viral". It can be counterintuitive but memes often work well when they don't make sense or use a range of "innapropriate" emotion - it creates an in/out group dynamic that makes "getting" the meme aspirational.
Memes are bad for educating and spreading large amounts of structured information, good for creating highly engaged groups of people that will then self educate and promote independently of centralised control.
Designing memes is an actual science. You can certainly get a lot of success in creating something that can spread just by emulating other memes that were successful, but to achieve a specific outcome within a timeframe can require actual design.
A lot of the original reference material for this predates people publishing things on the internet openly, but Dawkins for the basics (although most people are across his definitions of memes) and for more specifics on engineering memes I have tended to follow Blackmoores views, although she has since moved firmly into the territory of post human AI memes (memes that engineer memes) - which whilst highly probable do not help right here right now designing memes to get people to get other people to vote Pirate.
If anyone cares about this stuff, I can dig around and see what I can find for the reference material.