We know that we do not find all the bugs in the application under test (given that the application at hand is not simple). However, we do want to discover and report the most and the best bugs that we can. You need more ideas if you want to find more or better bugs than you do at present.
1. Understand Requirements Thoroughly: Ensure you have a deep understanding of the software requirements and specifications. This helps in identifying deviations and inconsistencies in the application.