I find usually the best roi is the nearest option to your predicted duties stock price. Ie if stock ends up 78. The 80 put will be best return. Best ROI is usually NOT THE BEST option. if it does reach 78 it will be worthless. ATM options are more expensive but higher probability of return. So it ROI vs probabilities of returns.
Good point. ROI is a fundamental goal. Most beginners would be best served by staying close to ATM until they get a handle on convexity effects. Primarily Gamma.