The first question I ask a service business is not 'what is your budget?' It is 'what is one booked call worth to you?' If you do not know that number, you cannot judge the campaign.
A good campaign has three parts: a clear offer, a simple landing page, and a follow-up system. The ad creative gets the click; the landing page gets the lead; the follow-up gets the booking.
Creative works best when it looks like organic content, not a polished ad. UGC-style testimonials, direct-to-camera hooks, and before/after stories usually outperform graphic carousel ads for service businesses.
Start with one campaign, one audience, and three creative variants. Let it run until you have enough data to make a decision, then kill the losers and scale the winner. Patience is cheaper than guessing.
Finally, retargeting is where the profit is. Most people will not book on the first visit. A simple retargeting campaign to people who watched 50% of your video or visited your landing page will usually deliver the best cost per booking.