It's no secret that despite being a great device overall, the  (2012) offers less than ideal flash memory performance. While the issue has been mitigated to a certain extent through the use of TRIM, file system performance is still often the device's Achilles heel. Because of this, it stands to reason that any steps taken to improve storage performance on the device will greatly improve the overall user experience.

XDA Senior Member legolas93 decided to take on the task of improving the Nexus 7's storage performance through the use of F2FS, which is a different file system created to be more optimized to the characteristics of NAND memory in flash devices. But before we go any further, it's important to note that when changing your file system, you will lose all of your data. So please make sure that you make a full backup, and then transfer that backup to your computer while you perform the required steps.

To get started, you must first download the F2FS-enabled kernel and a modified TWRP capable of reformatting the tablet with F2FS. Then you flash the kernel through your current custom recovery and the modified version of TWRP through fastboot. Next you access the modified TWRP and format to the new file system. And finally, you can restore your backup after copying it back onto your tablet form your PC.

More detailed instructions and all of the downloads can be found in the original thread. And if you're a SlimKat user, you may want to try this version modified to be fully compatible with F2FS.