in the past, i've always treated engineering like I do patients at a clinic or a hospital. in order to know WHY they are feeling or doing something the way they do, I have to KNOW what got them to that conclusion and how their mind is working. I don't psych them out. I don't try and hide what I do; I just try and establish a common ground so I - and he - can get a good job done with the best possible method available. Treating something a resume killer is perhaps not the way to view a client because, really, you could turn them away if you were so concerned about having ALL of your resulting work sound a certain way. The job of the producer and engineer is to prep and present a client's sound and stay true to what THEY intended the music to sound from their head onto disk, not the other way around. Otherwise, you had be better at playing all the instruments on a record because that might be the best way to assert your control over the favorable outcome of a record's sound. So, I would suggest a more intuitive approach that doesn't just get you to do a job but also present EVERY opportunity for the artist to get a particular sound across. You could start with asking what artists they like, records they always listen to and tones they admire. Start from there and ask them if you could have them try different tones that is more representative of the sound that they would really like because, maybe, they like particular sounds but can't replicate them because of gear limitations. As such, it is your job to open doors of opportunity and get them from tone point A to Point B; THIS is your job and your skill as a producer and engineer is what is at stake, not the potential result of a sound that you don't like. Afterall, you are recording THEIR music, not yours. DO your job but do it well with finesse and an open mind.
I spend quite a bit of time hanging out with band members before I even do a session. This helps me establish a good ground for communication and a creative environment that works well for everyone involved.