>>2460730samefag here.
Also, I know from personal experience that that advice is useless. My mother told me to just laugh it off and not take it so personally, which is exactly the right thing to do. It just isn't easy to do. It takes a level of self-confidence that I didn't develop for several years.
The right thing to do: Be really quick and think of a witty retort that'll both defuse the situation and make the bully look like an ass for trying to pick on you. I'm pretty sure every kid being bullied knows that, but that doesn't make the witty retort suddenly come out of nowhere. I mean, it's like saying "Be really charming and popular so that everyone likes you". In fact, it's what I did. I have no idea how I did it though. Plus, I did attempt suicide once, so I really didn't do it fast enough. Those were some painful years.
I have no idea what I'd say to the kid in your question. I do think most kids are picked on because they lack social skills in a certain area, and make themselves an easy target. Children are good at sensing weakness and will exploit any vulnerability unless they have an interest in being liked by you.
I guess one lasting result of my experience is that I don't have much time for people who think of children as sweet, innocent things. Children are vicious, amoral sociopaths until they learn compassion.
So here's the best advice I can come up with: Be stronger than them, be tougher than them, be more handsome than them, be more intelligent than them, be more quick-witted than them, make them like you and make them think that crossing you is a really bad idea. Sound easy?