When I worked at my 141 college program, we had a policy of instructors scheduling checkrides. This came from several instances where the students jerked around the DPEs, such as cancelling at the last minute or scheduling a checkride before getting signed-off. My normal routine was to discuss the DPE options with the student, pick one, then call them on speakerphone. This was nice because I could listen in on the conversation and make sure the student understood everything (like what to flight plan, etc.). During checkride season I used to call the DPEs every so often and get an idea of their availability, too. I always felt like it would be a poor reflection on me if the student messed up scheduling the checkride, and I liked maintaining a good relationship with our DPEs.
Another tip I preach is make sure you have a "pre-checkride" meeting a day or two before to proofread ALL the paperwork & logbooks, and be present when the student meets the DPE and starts the checkride.