Gestalt are 'rules' coined by gestalt psychologists, describing how people gestalts the world, meaning how they make sense of visual inputs. How do we make sense of user interfaces? We can benefit from the rules of gestalt.
1. The rule of similarity (if things look like each other, they probably belong together or have the same function).
2. The rule of proximity (if things are close to each other, they probably belong together)
3. The rule of continuation (if things are linked together, the eye follows the path and the is probably a natural sequence is the events).
4. The rule of closure. (If things are boxed in, we consider them as belonging together).
5. The rule of figures ground. The smallest closed area are percieved as an object first.
Look at the video or study this guide.
Pick a website of your choice and try to apply as many of the rules of gestalt to it.