The long answer comes from a great book called Influencing with Integrity by Genie Z Laborde (I wonder what the Z stands for). It takes the findings of the field of NLP (Neuro-Linguistic Programming) on communication and negotiation and translates it for the corporate world. In it, Dr Laborde talks about the concept of dovetailing outcomes – offering up the notion that the only way to get your outcome is to see that everyone else involved gets his or her outcome too. This may sound more difficult than it actually is.
If it appears that your outcomes are different from your participants, look for the opportunity to be flexible in what the end result is but not the need it serves. It’s good to distinguish that an outcome should be something like “decide how we will rearrange the office” NOT “the group will agree to my configuration of how the office will be set up”.
At the beginning of the meeting (or even before hand in any pre-meeting information), clearly state the purpose of the meeting and what your outcome is. Encourage the group to offer theirs (if different) and find a place where the two can meet BEFORE you proceed.