There are specific methods and tactics to improve your ROI.

In order to get a better ROI from your Google Ads campaigns, you have to analyze and optimize them at the keyword level, the ad level, the ad group level and the location level -if you have two or more locations you are targeting with Google Ads. 

You need to know the most important data to check, and what to do with it. Google is a very transparent platform, and you can have access to a lot of data from your Google Ads account, that, for the inexperienced eye, can be overwhelming. However, a good tip is always to have a look at what is not working and either decrease its bid and/or pause it. You can also try to increase the bids of those elements -be it keyword, ad or location- that are working and follow up a few days later.