Audio is much more important than video when it comes to the experience people have on YouTube. You can live with flaws in the video, but not a bad audio experience, that would make the content unwatchable. 

Here are 12 of the Best Tips to Instantly Improve Your Sound Quality.

Watch the video on YouTube here: https://youtu.be/LPfZL4cTrs8

START WITH AUDIO PRODUCTION 

It's easier and better to capture good audio up front than to try to save it in post-production later. The worst thing you can do is say "we'll fix it in the edit". If you can capture quality audio then you will have less work to do and won't end up with distorted overprocessed audio that distracts the audience.

Prioritize getting the mic as close to the subject as you can. This could mean using lapel microphones using a wireless lav system, or it could mean using a boom arm or just a shotgun microphone with the camera close to the subject.

You also want to try to have a less noisy environment if possible or consider some sound treatment. Combined with using the right type of microphone for the circumstance, this puts you off to a good start.

Little tricks can go a long way like capturing the ambient noise in the environment by letting the camera run for 5-10 seconds at the beginning and end of the video before you start speaking.

HAVE THE RIGHT TOOLS FOR THE TRADE

Different audio tools can help you when it comes to having better quality sound. For one thing, a great pair of monitor headphones will help you judge your audio better when capturing or editing the audio.

Even when filming by yourself you may want to check and monitor the audio using a pair of headphones before you start a set of recordings, by filming a short video and then verifying the audio.

Using a separate audio device to capture the audio or as a second audio capture source for backup could help a lot when it comes to interviews. 

Using quality microphones and recorders could get expensive but it doesn't have to be. Understanding what gear suits both your needs and budget is important. 

EDITING SOFTWARE AND TECHNIQUES

Post-production editing is something that many creators struggle with when it comes to audio. Be sure to learn the options available to you based on the software that you prefer to use. I primarily use the Adobe Suite so that would be Adobe Premiere Pro and Adobe Audition.

One of the simplest methods for helping to clean up your audio is to use "Adaptice Noise Reduction" another is "Noise Print Capture". These are two of the most common methods to clean up audio in post. 

You can also take advantage of audio presets or even make custom presets. 

These days I tend to use the audio editing tools in Premiere Pro with the Essential Sound panel and have made custom presets for my individual microphones. 

Eventually I plan to record samples with my each of my microphones under specific conditions and send them to an audio engineer to make me specific presets that give me the perfect conditions for reach of my mics when recording in my home office.

You can use audio-plugins to make your life easier in some cases but it is possible to go overboard. The main thing is to edit your sound by ear and try to learn as much as you can about your chosen software.