One of the best features of how the web works is that the underlying structure of every web site you visit is available for viewing and tweaking. The portal into that world is in the right-click menu on any web page: Inspect Element. Clicking it brings up the Developer Tools panel or window.
First thing to notice is the upper-left panel. This shows the HTML code that makes up the web page. As you mouse-over the elements, you can see them highlighted in the page itself. In fact, right-clicking Inspect Element on any item on the page should bring up the Developer Tools with that element pre-selected.
One of the most basic things you can do here is right-click on any element and delete it. Say, for example, you are trying to read an article on a page and a really annoying animated image is distracting you. Inspect, delete, and you are good to go. Or say you want to print out a ticket, but you don't want all of the annoying ads that they put around it. Yep, you got it. Inspect, delete, print.
The other thing you can do is edit the CSS styling for any element, which is shown in the Developer Tools' right panel. You can change its size, color, position... heck, almost anything you want about it. It does require some knowledge of CSS. But with auto-complete, you can experiment. First, start by just unchecking some of the existing styles and seeing how those change. Next, you can click at the very top of the panel where it says element and add your own styling. Type color, press tab, and then press the down arrow. You can arrow down through all of the different named colors in HTML and see how the element changes.
Sometimes you want to save an image from a web site, but a clever programmer is using tricks to prevent the Save Image option from showing up. You can Inspect Element, and by looking through the elements around the one that is selected, you can find the image hidden under a transparent overlay, or find it available as a background image.