What's the best way to make corrections to a published paper? Should I amend the original paper and mention in a footnote (or similar) what was changed and why or prepare a completely separate document and put that on my website/append it to the original paper?
I'm not so much worried about how to get it to the publishers that handle the paper, but rather about how to go about it. I would especially like to hear from people who have done something like that or know someone who did.
Journals oftentimes make their procedures regarding varying types of corrections available on their website (e.g., Nature). I would speak with the journal and see what their preferred methodology is. This way, you can have the correction listed alongside the original publication, which would maximize the visibility of the correction. Almost no one reading your paper will check your personal website to see if corrections have been posted there.