As a UX Researcher, I thought I'd share some of the things that have best facilitated the interdisciplinary collaboration between usability researchers and designers. Please free to add to this list based on your own experience.

1. GET DOWN INTO THE TRENCHES.  As a researcher, understand the candidate design directions.  Kneel down by the desk of the designer/research with whom you are collaborating so you are both sharing a screen. Fully grasp the design and technical limitations and why one direction might be more (or less) feasible than the others.
2. MUTUAL RESPECT.  Respect his/her expertise as a researcher.  Have him/her respect your expertise as a designer.  Try not to step on toes or cross lines.  Not always easy, but mutual respect will help greatly.
3. MEET EARLY AND OFTEN.  George Bernard Shaw once said “The single biggest problem with communication is the illusion that it has taken place.”  How true.  Meeting regularly will ensure that one party never assumes that you both have already tied out on an issue when in fact you haven’t.
4. PROVIDE RESEARCH ARTIFACTS TO THE DESIGNER.  And do so early.  Providing your designer with a set of UX tenets, heuristics, or best practices early in the design process will allow the designer to feel “untethered”, while these artifacts are simultaneously performing a perform a ‘grounding’ function for him or her.

Hope these help.  And please keep the list growing if you have additional design-research collaboration recommendations!