Write software that is loosely couple with high cohesion.
When you follow the SOLID principles (single responsibility principle, open/closed principle, Liskov substitution principle, interface segregation principle, and dependency inversion principle), your software tends to have smaller classes that work together more easily.
The classes will become more loosely coupled so that a change in one does not always require a change in another. The classes will also have high cohesion, meaning that all of its methods are closely related to the class’s primary responsibility.
When you arrange classes in this manner, you create systems that are easier to maintain and extend over time, which will reduce work for yourself and future developers as new requirements and feature requests come in.
These habits will also remove code smells, reduce complexity, and make the code easier to read. These techniques may be hard to practice at first, but over time you will get better, and the quality of your software will improve dramatically.