How Do You Build Backlinks?

Most estio agencies have strong capabilities around optimizing a page and doing the techtical side. Ask for samples ahead of time, both on link building, but also content. From what i hear, some of the biggest complaints people have about the so company is the contents terrible. It's just aimed for keywords with no real user intent behind it. Or doesn't take capture the s message. And then when you're looking to work with an c o firm, how do you kind of make sure you don't end up in this hat bucket hole?