One of the reasons that Google Ads turns out to be so expensive for many businesses is because they don't have their targeting set correctly (i.e. who the ads will be shown to.) Negative keywords are a powerful way to make sure that your ads are not showing for things only tangentially related to your business.
This is especially important if you're using "broad" matching types. You'll need to identify and segment your target audience and the keywords they do (and don't) use - then try a combination of phrase, exact, and negative keywords so you know exactly what your ads are showing for.
Experiment with different types of targeting, and setup conversion tracking for every ad, so you know where you're getting your best ROI.
Two words: Negative keywords
One of the reasons that Google Ads turns out to be so expensive for many businesses is because they don't have their targeting set correctly (i.e. who the ads will be shown to.) Negative keywords are a powerful way to make sure that your ads are not showing for things only tangentially related to your business.
This is especially important if you're using "broad" matching types. You'll need to identify and segment your target audience and the keywords they do (and don't) use - then try a combination of phrase, exact, and negative keywords so you know exactly what your ads are showing for.
Experiment with different types of targeting, and setup conversion tracking for every ad, so you know where you're getting your best ROI.