The first step toward growing your marketing ROI, is actually measuring it.
Lots and lots of business owners struggle with the immeasurability of their marketing managers' plans. Without robust measures, you can never know what's really working and what isn't. In the absence of this knowledge, it's only human nature to zoom in and over analyse individual, even anecdotal results. This typically leads to frustration for both the business owner, who hopes to find order among the chaos and their marketing managers, who would like to be trusted to do what they are good at.
So, a big wish of business owners, though you may not realise it yet, is that marketing were much more measurable.