Like any short-cuts list, these will only increase your time if you can commit the ones you use most to memory so they’ll integrate well into your workflow. I recommend printing this chart and putting it somewhere close by your keyboard so you can glance at it until they become second nature.
And remember, in order for these to work, you have to be in the visual editor. If you spend a lot of time over on the HTML side, you’ll need to switch over before you start writing and formatting your next post. I hope this list of useful WordPress short-cuts saves you a little time!