You don't offer miracle cures. If you're in consulting, you provide direction, technology, strategy, insight and procedures, amongst other things. But they have to make it work. If they don't see the vision they often won't buy, and if they do buy, they often won't follow through. Provide ongoing assurance, once the contract has been signed, that they have made the correct choice and that they are on the right track.
Many projects fail because of client apathy.
It's your job to hold a torch for that vision until the results create their own momentum. Write, rehearse, test and validate the words you use to sell the dream. This is not something you should just wing. We are facing an interesting time in our economy. With the crash of the Japanese economy you may wonder if we can't be far behind.