There's a recipe for projects that get done smoothly, on time, under budget, look great and work like a charm – not only for happy clients but also the people clients want to impress. 
Designer Bonnie Siegler wrote Dear Client: This Book Will Teach You How to Get What You Want from Creative People, a book so beloved I've summarized some parts below.  (There's also a YouTube video.)

Recipe for "Wow, that was easy!" projects:
1. What's for dinner?
Let's talk about your priorities and expectations.
Example: many logo clients mention iconic Apple and Nike logos as examples of what they like. While that level of recognizability has more to do with well-funded, consistent use over time, what I deliver positions you for success.
Imagine you'd been present when Nike and Apple's logos debuted, you might have wondered what boomerangs have to do with shoes, or apples with innovation. Today they're gold standards, and they're not even literal!
Today's special: a beautiful partnership with a side of wings.
2. Ingredients
Sending content that's already finalized (edited, proofread, etc) saves time and money, as does sending all content at once with minimal text formatting.  Artwork requirements vary by project, but aim for files that are at least 1MB in size.
Pizza is greater than the sum of its parts, but you still need all the parts to begin with.
3. Serving Size
White (or negative) space is a term for areas without design elements. It draws people in (rather than being overwhelming) and helps them recognize what your priorities are.
If someone throws one tomato at you, you might catch it. If someone throws ten, that's a cleanup in aisle 5.
4. Taste Test 
Supply your goals rather than a solution, such as wondering if something can look sunnier or brighter instead of specifying we "use yellow." 
Want to become a designer's favorite client? Supply a single point of contact that consolidates feedback. On the other hand, if you want to specify most aspects of what your project looks like, that's great – but you don't need a designer.
Having the chef to hold the onions is one thing; asking them to follow your own recipe is another.
5. Indigestion 
As Bonnie Siegler says, great work doesn't come from consensus, it comes from partnership with a decision maker with vision, leadership skills and support from stakeholders. 
Asking people to weigh in if they don't have "skin in the game" tends to backfire. Recommendations cancel each other out, and negative comments often eclipse positive ones. 
"Too many cooks" spoil pizza. And projects.
The biggest takeaway:
Designers learn over time what makes a project take longer, cost more and yield results that no one's really happy with. I'd much rather make less and deliver a project in half the time if my client is thrilled. That's where you come in.

Cheers!