Link building is kinda a dying thing in some ways, but a lot of sites still allow people to paste their site. Either it be in a comment section where they allow you to list a website. Or maybe even forums that allow you to insert a link in the signature, which means each post you do, helps out.
The only thing is, a lot of sites also don't allow advertising or promo, so you have to be subtle about what you promote.
The only thing is, a lot of sites also don't allow advertising or promo, so you have to be subtle about what you promote.