You can negotiate this in the agreement. For example, the agreement could give you control over what advertisements and point of sale material are used. It could require the distributor to run particular marketing campaigns or spend a specified amount of money on them. The agreement could also require the distributor to maintain an adequate stock of your products.
The distributor might negotiate for you to provide them with marketing support or a contribution to their marketing costs.
If the distributor wants exclusive rights to a territory, you might also aim to negotiate a minimum sales target.
