Just inspect the element you want to hide, and add the
display:none; property to it. you can test it first using your explorer [Chrome, Firefox, etc]
I did a quick test on the Davinci Woo theme by Alidropship, and here's the CSS you need to add to your site [Not sure if WOO has just a button to hide this stuff]:
/*hide rating stars*/
.woocommerce div.product .woocommerce-product-rating {display: none;}
The text between /**/ is just a CSS comment to let you know what is that CSS doing, just to stay organized.
Here are a couple of screenshots on how to find the element CSS rules...