Gestalt principles and Fitt’s laws are very useful for designers to keep in mind while designing interactive interfaces.

While making a software, I  would consider Gestalt’s Law of Proximity to ensure that I am grouping elements that have similar usage or are used together more often, to make navigation more intuitive, while also maintaining visual balance within the elements (making grouped elements have similar shape, colors, or visual traits). I would also try to use familiar design patterns as it makes it more intuitive for users to interact with the interface. 

For Fitts’s Law, I would focus on optimizing target size—especially for frequently used actions—by making buttons larger and easier to tap or click, thus reducing the time and effort needed to interact with them. Placing targets closer to the user’s hand position/cursor makes it easier for them to reach, so I would consider keeping elements like menu items either at the screen’s edge to avoid overshooting, or somewhere in the middle, depending on whether it is a mouse driven or touchscreen interface. As linear menus are most common, I would use them and place items according to the frequency of their use. Lastly, I’d be mindful of space between targets to prevent accidental clicks on adjacent buttons, particularly in mobile or touch-based interfaces