Three clues from your own business
Collect the English questions you already receive. They show which information is missing. A general hope for more reach is a weaker starting point.
A restaurant might start with its menu and opening hours. A tradesperson may need services and the area covered. Art products need a clear ordering process and delivery information.
Not every page needs a translation immediately
Start with services, key terms and contact. An English button leading to a German form only solves half the problem. Include confirmations and error messages too.
Be clear about the conversation that follows: can you answer questions in English? Say so.
Language selection and Google are different tasks
Device language and search engines require different solutions. Google recommends separate URLs for language versions and appropriate language annotations. Changing text on the same URL is not equivalent.
KitePages has German pages and English versions under /en/. Visitors can change their selection at any time. English does not necessarily mean abroad: the person may live next door.
The real extra task is maintenance
When an offer changes, both versions need checking. Decide who maintains prices, services and contact information. Machine translations need review, especially for commitments.
Start short but complete. Then check whether the English version brings useful contacts before expanding it.