Partly by getting control of the local party apparatus. Most of those in urban areas are nothing but either just social clubs for a few remaining aging elites or liberal dilettantes (see Massachusetts) or they’re outright rumps of the Democrat party that get patronage crumbs from the Dems for agreeing not to challenge their supremacy (see Philadelphia). Bounce out the local fossilized frauds and rebuild from scratch, it’s the only way.
I don’t see what you just said in your post actually happening anywhere! Where are the conservative special interest groups that are just focusing on how to successfully get conservatism to actually exist in big cities throughout the U.S.? Even when the GOP makes any kind of political inroads in U.S. cities, they are usually RINOs and not actual conservatives!