So many people miss this one that it deserves real attention here. Win/win - the only way to roll.
If the deal isn't good for your customer, then it just isn't good. If it isn't in their best interest, don't do it. This is why I always counsel my clients to listen and respond. Don't sell what you want to sell. Sell what the prospect needs.
Not only will you make the sale but they will refer you so the rewards will be greater than just that one deal. However, if you only think of yourself and sell what YOU want to sell, you will only have that one deal. AND, not only will they not refer you but most likely will bad mouth you. That kind of press you really don't need. What started as a win/lose becomes a lose/lose.
No one can stay in business for long with lose/lose. It's the win/win folks who grow and prosper year after year, beyond their wildest dreams. Who will you be?