Desktop Neon Effect LED Signs


I'm going over some projects with friends to study them, as we were told it's a great way to study. Currently, I'm a bit stuck with one of the projects:

What are some advanced techniques for optimizing power efficiency and reducing EMI/EMC in the circuit design of a neon effect LED sign like the one in the "Desktop Neon Effect LED Signs" project? How can one implement any specific circuit elements or design considerations, such as using a switching power supply or shielding, to address these issues? Also, what measures were taken during the PCB layout to minimize cross-talk and signal interference between the various components and sections of the board?

Thanks in advance!