I pick a niche, for examples I have dental clients for SEO.
I will search for dentists on google, check out their websites, ranking, domain authority and backlinks etc. find out who the owner is, connect with the owner on LinkedIn with an intro message.
Send an email, not selling anything, just explaining that I am local, who I work with and what results I’ve achieved and whether they would like the same results then follow up with a call two days later.
If they are slightly interested, I send them an email with a 1-2 demo video.