If you would like a guide that you can read but with pictures showing how to do stuff check out my Steam Guide and if you would rather watch a video tutorial check out my video. (If this helped please subscribe to my YouTube Channel <3 )
Graphic Settings (In-Game)
Once you're In-Game press ESC and click on Graphics. Make sure V-Sync is Off and that Max FPS is set to Max.
Some users have claimed that settings all other settings to Low, restarting the game, then setting it to high and restarting again improves the Performance and increases the FPS. Worth a try!
First off, close the application if you have it open.
Open the explorer, head into your No Man's Sky Folder which by default is set to C:\Program Files\Steam\SteamApps\common\No Man's Sky
Once you're in the No Man's Sky folder, open Binaries, Settings and open TKGRAPHICSSETTINGS.MXML with a text editing software. Find the GSync line and replace "true" with "false". Save it.
Configure Settings In Your Graphics Card Control Panel
I have the Nvidia graphics card so for those of you who are using something else, try finding a way to do it but in your graphics card control panel.
Open up your graphic cards control panel (in my case Nvidia). Click on Manage 3D settings and click Add and add No Man's Sky. Scroll all the way down to vertical sync and set it to off. Set triple buffering to On and Power management mode to Prefer maximum performance. If you are unsure about the other settings, just copy mine and make sure they match.