How to start web dev company?

Hey guys , I've been into web developing for years now but I always did little freelance jobs, now I've decided to set up and get into bigger projects as I have more free time , the thing is I'm not sure how can I pitch myself or reach companies that need websites to be done, should I physically visit local businesses and companies or cold call them offering my services and thing of something they might need?

Also I'm not a pro in off page SEO , should I hire somebody and offer such services or learn it myself?
I want to start small and grow big , but how should I start?

Physical visit can be not so easy (schedules, etc)
Maybe try to find companies that possible need you (shit web) and text them with samples of your work