For most users, this is the real payoff of Keynote keyboard shortcuts: not memorizing everything, but speeding up the repeated actions that shape the whole workflow.
Start with slide-level actions first. Learn the combinations you use whenever you create, duplicate, or delete slides, because those are the commands that repeat in almost every deck. If you need a simple study aid, keep a cheat sheet beside your screen and focus only on your most frequent slide actions for a few days before adding more.
Next, focus on editing text and objects text formatting, working with tables, manipulating objects, and applying styles. If you build slides with recurring design patterns, treat the most common formatting actions as your personal Keynote keyboard commands so they become automatic instead of something you have to search for.
Presentation mode is its own skill. Practice the commands that start a slideshow, advance through content, and help you stay oriented while speaking. This matters even more if you present from different devices, because it is designed to work across Mac, iPad, iPhone, and the web. The faster your presentation controls become, the less mental effort you spend on the software while you are in front of an audience.
Finally, learn how to move through long presentations and across platforms. If you often edit in a browser, review the Keynote iCloud shortcuts that matter most for your workflow, since Keynote on iCloud is intended for use on a computer and supports web-based editing. For many users, the most valuable quick keys are the ones that help them move smoothly between slides, views, and editing contexts rather than flashy one-off commands.