[User23]

Giving unsolicited advice is disrespectful and will do your relationship with the person in question no favors. Contrariwise, soliciting advice from someone else is respectful, and will often improve their disposition towards you. The simple rule that I endeavor to follow is to never give unsolicited advice, but to give solicited advice if I can be helpful.

A blog post isn't unsolicited advice because nobody reads it without choosing to visit your blog. Incidentally that indicates the reader has at least some respect for your thoughts. It probably won't be as helpful as personalized solicited advice, but it's still potentially valuable.

Another rule I follow for advice-giving is asking myself, am I suggesting a way that is really better or just how I would do it? If it's the latter case then I'll often demur, or at least say it's really just my opinion and there are probably other, possibly better, ways to do whatever it is.