Perhaps counterintuitively, students that finish first and have a fully-functional design almost always work slowly and deliberately, and do not move to the next step until they are sure what they are working on is correct. Perhaps the best advice is to think hard and resist the temptation to start layout until you are sure your design is likely correct and what you want.
Other suggestions include:
thoroughly understand the requirements and design everything on paper before anything else
draw a well-thought-out circuit diagram before starting your stick diagram
draw a well-thought-out stick diagram before starting layout
draw a well-thought-out floorplan before getting too far into your layout
thoroughly debug and test complex components (e.g., arithmetic units or larger blocks) with a wide variety of input data before testing more complex systems (e.g., ..., core.mag, top.mag)
occasionally back up work
of course do not start work on a large project a few days before the due date
a design with an impressive area and delay requires at least a second complete version
2018/10/26 Written (BB) 2023/12/02 Fixed minor typo (BB)