I learned a lot by trial an error; when I first started out, I'd explain every little detail to my clients. I quickly learned they were only interested in the big picture: a clean website and lots of organic Google Page 1 Listings!
I always listen to my clients' suggestions and if their ideas aren't feasible, I offer workable solutions. If I don't know their industry, I ask questions and do my own research to get up-to speed. I'm also very intuitive, often knowing what my clients want long before they do! Consequently, they're more than happy to refer new business!