The best thing that you can do to improve the production values of your YouTube content is to buy a wireless mic kit. Your DSLR or smartphone will capture good-quality audio from a foot or two away from your mouth, but that quality drops rapidly with each extra foot you step away from your camera. Built-in mics are also very prone to wind noise at any distance. By clipping one of the best lavalier mics to your lapel (and plugging a receiver into your recording device) you can keep your mouth close to the mic at all times and capture clean clear sound from a distance from your camera - up to 200 meters in the case of the Godox WES Kit.
