It is important that you don’t make any demographic presumptions before starting a campaign. Let the data show you what type of customers are the type to convert. After 3 – 5 days running your campaign you can start to optimize it. Just click on a “Breakdown” button in your Ads Manager dashboard and check these parameters.
Look for the best converting age group, push the entire budget to that age group, excluding others.
If you could see that either men or women are converting more on your products, exclude the other gender and leave only one.
This is a more time consuming and precise process. I would recommend you not to optimize regions at the beginning (e.g., U.S). If you are targeting several different countries in the same ad set it is ok to optimize if any country is dragging the performance of the ad set down.
Facebook has several placements to show your ads. It could be a News Feed (both mobile and desktop), Right-Hand side, Instagram, or Audience Network. After 3 – 5 days running ads on several placements (e.g. both Newsfeed and Right-Hand side), take a look at placement breakdown metrics and exclude the ones that aren’t converting while burning most of your budget.