In this guide, I will run you through the very basics of setting up GTA V and RAGEMP, if your game isn't working or isn't working as well as it should be please follow this guide and it may fix some of your issues.
Installation:
To ensure the smoothest experience make sure that both GTA V and RAGEMP are installed on the same storage drive, you can install them on alternate drives but it has a chance of causing issues. I also recommend installing via Steam as the R* games launcher version has its own issues for whatever reason and doesn't work as well with RAGEMP.
Settings:
Already installed GTA V and need to move your game install?
RAGEMP settings, here is what your settings look like; the client should initially run as administrator by default.
Everything is turned off, this ensures that no additional settings are running and this is what the server recommends.
Notice that the game installation and RAGE are on the same drive.
Graphics + Advanced Graphics Settings
The most important ones here are that you are running the game in DX11, Fullscreen and using your monitors correct resolution and refresh rate. As for advanced graphics for whatever reason, running the game at 3/2 (1.500x) seems to make it run a little better.
If you are running into FPS issues, make sure MSAA is turned off, advanced settings (with the exception of Frame Scaling) are turned off, and Grass isn't on Ultra/Very High. In future I can make an in-depth guide to an FPS boost.
Graphics Card Drivers
The number one cause of crashes in RAGEMP I see are people not updating drivers, ensure that they are updated through either Geforce Experience or AMD Adrenaline.\
In-Game Overlays
In-Game overlays such as Steam, Discord, Teamspeak, Overwolf, etc currently can cause crashes, make sure to disable all of these at least for the time being.
Thanks to @sebu for bringing this to attention!
Did I miss anything? Reply below and I'll get it updated.