Acting as a Financial Analyst, calculate the return on investment (ROI) for a marketing campaign aimed at increasing sales. Provide a detailed breakdown of the initial costs, revenue generated, and indirect financial benefits. Offer insight into how the ROI can be improved in future campaigns by adjusting key variables such as marketing channels, target audience, or ad spend. 
<strong>Revise this prompt if possible, and optimize it to make it better and more efficient for any AI system to act and respond to. 
If possible run your optimized version.</strong>