To focus on the next and previous elements on a web page, you can use the Tab and Shift+Tab keys, respectively. Depending on your goal, that might result in having to press the same key or key combination many, many times.

You can navigate faster through the whole page with just the keyboard using Spatial Navigation. While holding down the Shift key press the arrow keys to move to elements left, right, above and below the currently highlighted element (has an orange border around it). When you’ve focused, for example, on a link on the page, press Enter to open it.