The hardest balance is when to show stakeholders mockups that look 'real.' You don't want to get caught up in font wars or 'i don't like that blue' too early in the process, but non-designers often need something more concrete than a wireframe to really engage and envision the outcome . I like to inject style boards looking for what kind of 'mood' the site should evoke perhaps a bit earlier than most to get that conversation started and direct people's imaginations in that right direction.