If there was a special stick (or wand) that would allow sales and marketing to level customer demand, I would beat the sales and marketing people with it daily. However, the real culprit is customer demand, and if you are a job shop, it is very tough to convince your customer that he should place his orders in a manner that is most convenient to you and your shop loading.
That is not to say you cannot gently prod the customer in that direction. However, in order to do that you must be willing to change internal practices and embrace many of the principles of lean.
In order to "encourage" my customers to level out orders, we embraced smaller lots more often. This required many internal thought changes, including the elimination of setups, and having a cross-trained staff (at least the key individuals). Just saying smaller lots more often does not make it happen: We "encouraged" the customer by offering one-price any-quantity pricing. We then suggested that the customer break his needs into monthly or weekly releases at the one simple price (note that our one price was typically the price he was used to seeing for large orders).
We then reminded him how good this is for him as he will not have excess inventory; his cash flow will improve as he is paying for only the parts he needs, and we can both be more flexible to market demand as we almost always have parts in process so we can adjust to more or less parts quicker. We benefit too, as we can get more efficient at running parts the more often we run them (practice makes perfect). We do not have all our eggs in one basket at one time, and we can satisfy more customers as I can have a wider variety of parts in process at any given time.
Even then it took some time to convince some customers that this was a good thing, so expect to take three steps forward and one step back from time to time. Most critically, if your process is not in tune to running smaller lots and reacting quickly to change and if your team is not on board, you will fail. Then someone will need to beat you with the magic stick. -- bradintx"