How can I respectfully decline unwanted parenting advice from others?

I personally dismiss any parenting advice with a polite smile, nod of my head i then offer back the methods i have been using and heard of that i feel have been or would be more successful. or if its rude and intrusive i simply say "its okay, i have it thanks, sounds really great it worked for you"

By being respectful and saying "thank you for caring" then go do what you think is right for you and your kid/s.

As a parent, especially a new one, people find giving unsolicited advice to be “helping”, but it doesn’t always. It can leave you feeling inferior, or like you can’t do things your own way. That is YOUR child, and you know what’s best for them. Politely tell people, thank you for the tip but I’ve got it. If I NEED help, I’ll let you know. It can be difficult to shrug it off, but you just have to. And if people are getting too pushy, or putting their own advice to work despite your request not to, then you must be stern. Children don’t come with instructions printed on their backs. We learn as we go. And not all “advice” is helpful. Even if they want it to be.