I am not talking about spam and mass media, no.
I'm talking about useful comments with questions to the author and with tips for the whole audience.
How do you find blogs to comment on? Those blogs where commenting is allowed.
For outreach i used
Food intitle: "write for us" inurl:"write-for-us"
food (intitle:"write for us" | inurl:"guest post guidelines" | inurl:"guest-post")