One tip I picked up from working at a machine shop is make a quick vice end stop if you are making many identical holes or features on parts.
You can make them or buy them for most vice types, and they can make your life much easier.
This device is also amazing if you decide to take the part off to test it and must re-install it on the vice for further machining (for prototyping and the like).
Another must-have tool for machinists is an
edge finder. They are very cheap and can be quite accurate and precise. As long as you have a smooth surface to use it on you can get very tight zero locations on your CNC machines. I used a regular $15 edge finder at a reference standard company that required location tolerances of 0.0001-0.00005" and with some practice the edge finder was able to get those tolerances (not that you will need anything near that in FRC).