Need help with cold calling / first approach for off line and on line creative services

hey... so i categorize myself as a content creator. Im a photographer / videographer / music producer that has had professional experienced in all 3 paths before (i worked in a magazine as a photographer as well as worked with grammy nominated artist, i recorded and edited a youtube series with more than 3M views to date and have worked in big name record labels as an audio engineer/ producer) even though most of the work has been with friends or closed network kind of work.

I have also worked creating content and managing social media pages such as fb pages, ig and youtube channels for artists and clothing stores but I dont have access to them any more.

I want to start offering my services to small to medium businesses, mainly photo/video or social media but im having trouble on how to make that first approach? should it be in person? email? call? what should i present to them? should i make a small presentation tailored to their own business or more general information on what I can do?

I have almost all this content but i do not have a formal website or demo reel to show and have never worked for businesses before other than friends clothing lines stores... so should i do a couple videos for free to built a professional portfolio first?

Any one have some tips on how i can proceed with this?