The basic idea is to make a post on your own journal with the advice that you wish to say, and make a comment on the post where you wish to offer the advice with an explicit "Would you like advice on this? If so, I can make this post (with a link) visible." That has the advantage of avoiding the need to wait to write down your thoughts until the NAK/ACK is received, but not burdening the recipient with any more than the knowledge that you chose to use your own time to write down your thoughts (which hopefully won't be read as an imposition).
Yes, this is an example of itself (and kinda excessive for it, but it provided a good excuse for an example).
(edited: made visible after ACK received.)