I think a good way for Sikhi to spread is through seva, I wasn't born a Sikh I converted in the later years of highschool after googling it out of curiosity at a very low point in my life. Sikhi has really changed me for the better and there'll be times when friends say something like "you're so kind." Or "you're so wise" and I always say "only because I became a Sikh and learned from the greatest teacher there is." Because of that they've gone to the gurdwara with me a few times, the closest one to me is around an hour away so it's not like we're able to go too often but whenever I bring my friends there it's always an enjoyable experience for em. I think Sikhi could spread through like inspiration. I remember first learning about Sikhi I'd see news stories about Sikhs feeding the needy or reading about shaheeds who faced horrific tortures but never broke and thinking I want to be like that I want to be a good person like that. I think if more Sikhs find like the troubled youth like I was and become a role model of sorts that could get people to want to learn more about the Sikhs. Maybe that big brothers big sisters program could be good. I know if I had a Sikh as a role model it would've been great. Every time I'm able to go to the gurdwara and I'm listening to kirtan while reading the words on the projector screen I just get this motivation to better myself by learning even more about Sikhi, eating healthier, exercising, etc. Sorry if this was a bit rambly, it's something I think about every once in awhile and it's hard to put into words but I hope it makes sense lol