There are no "best settings." Please understand that every setup, for every use case, will be very different. Any guides or videos that claim otherwise are misinforming. Your best option is to start with a base and adjust as necessary. Test, test, and test again. We are happy to offer suggestions for any issues you may be having, but we will not give you a list of settings.
For high-quality, no fuss recordings, use the recording quality presets under Settings > Output when in Simple output mode. In the recording section, change the Recording Quality to Indistinguishable Quality, and then select your encoder.
Use the autoconfig to determine what your PC and connection can handle for streaming settings, and adjust as necessary. It can be accessed from the Tools menu in OBS, and then just follow the on-screen directions. You can use this tool to get a set baseline settings for your hardware. Lastly, please note that the wizard is currently in beta!