Minecraft wiki entry for Improving_frame_rate, associated text: Turn down your render distance.
Set Maximum FPS to Unlimited; however, lower-mid end PCs will experience stutter.
Reduce Graphics from Fabulous! to Fancy or Fast.
Turn off smooth lighting and clouds.
Reduce your FOV.
Set Particles to Minimal.
Turn off V-Sync.
If the mouse cursor is lagging, change the mouse sensitivity to HYPERSPEED!!!.
Disable mipmaps. Note that this can result in water/lava drips not being visible, and thus taking a lava bath.
Disable biome smoothing.
Reduce the size of the game's window, as this makes the game render less, making the game run a little bit faster.
If your computer has a better graphics card, you might want to enable full screen, as this will make your GPU focus more on Minecraft and less on other programs. Test both ideas and see which setting works best!
Install OptiFine or Sodium to adjust settings to better suit your computers architecture. Note that Sodium only supports Minecraft 1.16+ with Fabric and can't be installed together with OptiFine, but provides significantly higher performance on most PCs. Either mod[note 1] can be paired with Starlight and Lithium to speed up lighting updates and general game systems respectively. Phosphor may also be used in place of Starlight, although Starlight is several times faster than Phosphor. You cannot run both Starlight and Phosphor at once, so it is suggested to use Starlight.
If your computer is hot or your fan is loud, avoid running mods which add a lot of content and don't do anything that causes your computer to run a lot of calculations. This means closing any browsers or other games.