Do I need to set an audience, interests or lookalike audiences for my Facebook ads?

No. For most Facebook ads you do not need to pick interests or narrow the audience. Meta's AI decides who sees your ads based on how people behave with them: how fast they scroll past, whether they hesitate, watch to the end, read, click or open the comments. Your ad creative is the targeting.

Leave the audience broad, for example everyone in the US aged 18 to 65 plus, and leave age on the default. Every limit you add (age, gender, states, interests) starves Facebook of data and raises your cost per lead, while a bigger audience usually lowers it. The one exception is a local business that can only serve people nearby, or a local agency, where you set a radius around a ZIP code or area, for example 5 or 30 miles. Lookalike audiences only potentially help once you have data, and these days they usually do worse than setting no audience at all.

Because the ad does the targeting, design ads that make only your ideal client stop and everyone else scroll past faster. The simplest way is to call out your audience in the text or image, for example "Attention HVAC business owners" or "Attention personal injury law firms". Write in the language your audience uses: an HVAC owner says "service appointment booked", not "sign a deal". Avoid content that appeals to everybody, such as a funny cat or dog video, because it teaches Facebook to find people who like funny videos rather than your buyers. Small variations of an ad, such as a new air conditioner versus repairing your air conditioner, reach different pockets of people. This matters most for a new Meta account and a new pixel with no data.

Once your pixel is installed, do not send friends and family to your site at first. Facebook learns from who visits and will target people like them. Share it with your ideal clients instead, for example in relevant groups.