Here’s an older thread which focuses mostly on the GND planes/zones and options for how to place vias and tracks: Beginner's questions before sending for print - #13 by eelik. You, too, could add something like 100 vias and all empty areas would be covered by copper.
(Personally I wouldn’t use 0R resistors to jump over tracks. There are also contradicting opinions about putting tracks together vs. keeping them apart. This depends on the circuitry and how it works.)