Getting the best results with Google Ads as an advertiser

For those with some knowledge or experience of advertising, especially those who’ve used Google Ads and those who offer professional services, what have you found to give the best results?

I’ve never advertised and I’d like to make the best use of my advertising budget.

I already know to think in terms of what the potential customer will look for, not use jargon, give a brief description of what I offer and what sets me apart, use action verbs.

I’ll be using negative keywords to avoid particular clients who are squarely outside my specialty. I’ll also be using the geographical limit feature to only show up on the searches of local clients.
What else woudl be useful to know and do when publishing ads for professional services on Google Ads or, more generally, advertising?

Have you visited Perry Marshall’s web site, or bought any of his books?

No but I will, thanks very much.