Learn to play golf by practicing 15 minutes a day

This is quite a problem to solve, but just doing without greeking text won’t fix it. Using test items of real content and data in designs will help, but there’s no guarantee that every oddity will be found and corrected. Do you want to be sure? Then a prototype or beta site with real content published from the real CMS is needed—but you’re not going that far until you go through an initial design cycle.