Ideally pick a style from a different large organization that you have no input in. Because the organization is large they will have put a lot of effort into it, but since you have no input you can just follow it without thinking. Sometimes an organization will make some really weird choices and you will be forced to change styles (google as rejected a lot of the latest C++ standard and thus their C++ style guide is not to be used elsewhere, but there are plenty of other good options).

Second best is to start a large cross company standards organization and only allow one representative per organization. Make sure there is a lot of process standing in the way of changes so that changes are only made when really justified (because most are not justified)