Step 1: Find a post that seems constructive. Shitposting on a shitpost doesn't gain as much salt since everyone is doing the same thing you are
Step 2: Dig deep and find the most irrelevant, cancerous tumblr reddit brainchild of a sentence you can find. If you don't have the mindset for it or you're not familiar enough with the ways of cancerbending to do so please refer to one of your mentors such as @Flutterz or @VirginSmasher.
Step 3: Repeat this as often as possible to establish yourself as a reputable shitposter.
Step 4: Make sure your shitposting maintains consistent quality. Only have 1 or 2 good shitposts out of 500 makes you an irrelevant tryhard.
Step 5: Be extra salty (Like @solidbatman).
Step 6: Remember all tastes and opinions are shit in the shadow of your own. Insult someone's taste as often as possible
Step 7: Post count is life.
Step 8: Fuwachat is where you should spend most of your time to practice your shitposting and gain new techniques such as when to kek, lel, > and abusing the /me function.
Step 9: Play F/GO or Kancercole and claim to love it for the waifus then proceed to talk about it excessively with other shitposters
Step 10: Never be relevant and constructive.
Now that you know how to be a shitposter go out there and use your talents to better society. Stay salty my friends.