How do I target interests or keywords in pop networks?

[Flavor]

I've been experimenting with targeting interests in pop networks and I think I've found a good approach. Most pop networks allow you to target specific keywords or interests, so you need to identify what your audience is interested in and target those. For example, if you're promoting a weight loss product, you can target keywords like "fitness" or "health". Some pop networks also allow you to target specific websites or categories, which can be helpful. What methods have you guys tried for targeting interests or keywords in pop networks?