I’ve had a totally broad audience work on a great offer, but typically you want to narrow it down by demographic at least a little to help the algorithm figure out your ideal audience more quickly. Take a look at all the breakdowns available in your ads manager columns and see what trends you can spot about your past customers. Age, gender, device type, particular states, etc. And if you’re selling expensive travel, maybe you can narrow it down to the top 10% income zip codes (in interest targeting). Get creative and test a variety of audiences to see what works best.