How do you search for the best sites to comment on blogs? (Link Building)

Everybody knows that one of the good ways to link building is blog commenting.

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")

Here are some footprints that might work for you -

WordPress – “mail address will not be published” “Powered by WordPress”
Joomla – “Powered by Joomla!” “Write comment” “Website:”
B2Evolution – “Your email address will not be revealed on this site.” “Leave a comment”
Drupal – Powered by Drupal + “Web page addresses and e-mail addresses turn into links automatically.”
4Images – “Powered by 4images” “Author:” “Comment”
BlogEngine – “Powered By BlogEngine” “Add A Comment” “Name*”
SquareSpace – site:*.squarespace.com “Post a New Comment”
SharePoint – “Built using the SharePoint” “Comments”
Geeklog – “Powered by Geeklog” “The following comments are owned”
Plogger – “Powered by Plogger” “Post a comment:”
Movable Type – “Powered by Movable Type” + “Post a comment” -movabletype.org

That is very good list of keywords and will definitely work if the site owner did not change that to custom phrases.
But I would agree - in the most cases that will work !