Mwa ha ha ha ha I'm the mad sports programmer (sp) Hououin Riela! I was busy stopping the organization plans and didn't had time to write blog entries.
My archnemesis teja[some numbers] once told me that I was shit posting too much and I should start writing contests, so I searched in the web and found some problem setter guides:
codeforces: https://codeforces.me/blog/entry/49569 (It took me a while to find it, I think it should be more accessible in cf
topcoder: https://www.topcoder.com/tc?module=Static&d1=help&d2=problemWriter&node=algo_write
codechef: https://www.codechef.com/problemsetting
hackerearth: https://www.hackerearth.com/docs/wiki/developers/setter-guide/
It turns out that online judges pay for writing problems! I know that most people set contests just because its fun, but the payments are not negligible:
codeforces (300$ for div1+div2, 150$ for div2)
topcoder (750$ with that amount no wonder why they have high quality problems!)
codechef (They pay per problem, for short contests 475$)
I don't know how much they pay in hackerearth, hackerrank, ...
Now I'm curious: are there professional problem setters that makes a living just by writing problems?