Step 1: Make sure you use sufficient tags. EG: this tag says teaching, but other tags should be used, such as "Memes" "Stealing" and Reposting"
2: When you make a meme, click on the tags to see if someone else made the same meme. If so, look at the date. Chances are, if it's over a year old, it should not be considered a repost. (Note: check all memes that appear like your meme.
3: there is no rule 3.
4: When in doubt, refer to rule 3.
5: don't be a wimmlebutt.