If your ad campaign fails to generate profits, you will lose the money invested in your campaign. To calculate your ROAS, you need to divide the generated revenue by the amount spent on the campaign. To spend more without lowering your ROAS you can do the following. Increase the generated revenue while stabilizing the costs. Lower the ad costs while maintaining your revenue. Increase the revenue while you lower the costs. To achieve the above-mentioned, you can Improve your website, Assess what your competitors are doing, Refine your keyword targeting, Include geo-targeting, Optimize landing pages, Optimize your conversion rates, Promote seasonal offers, Use the negative keyword feature. There are other things that you can use to ensure that your return on ad spend stays above board.