Hello, my name is Megaparsec and I'm here to share with you some tips and tricks about audio engineering and sound quality I learned when I was a voice actor. Have fun! ^^
1. Microphones- You'll hear lots of people recommending Blue Yetis and Blue Snowballs. I, personally, have heard people recommend them all over youtube and the gaming community. While they do work well for a USB microphone (a microphone that plugs in directly to your computer rather than plugging into something called an audio interface), I would not buy a Blue Yeti/Snowball. You can get microphones that do the exact same thing- even ones that function better, for a much cheaper price. The only Voice Actors I've ever honestly heard use either of them were beginners, and didn't know any better.
Blue Yeti price: $130
Samson C01U price: discontinued, but I've seen them go for $40-70
CAD Audio U1 price: $25
HOWEVER, if you want to go FURTHER UP in quality, I'd recommend getting an XLR Microphone. These microphones do not plug into your computer- they plug into an interface that then plugs into your computer. This dramatically increases quality by letting you tamper with the audio input directly. This is usually more expensive, but I'd 100% recommend them for singers, musicians, or voice actors- or gamers who just really like good sound.
I use a Behringer U-Phoria interface, which I bought for $30, and a Shure SM48, which I bought for $40. Keep in mind that sometimes the interface doesn't come with a cord- but usually those can be bought for under $10 unless you want a super long wire. Keep in mind that your headphones won't work on your computer unless they're plugged into the interface- once the interface is hooked up, that becomes your computer's sound.
2. Programs- Audacity and reaper 100%. Both are free programs that can be used to record sounds (and the latter can be used to work with MIDI files), and while the latter is more complicated, it works phenomenally once you learn how to use it. I have more experience with audacity, and while it's a little bad with multiple tracks, you shouldn't need too many unless you have really intense audio requirements- and in that case, why are you using Audacity?
3. Miscellaneous Tips-
Speak into your microphone at an angle- that way, less saliva flies into the mic, and harsher syllables aren't read as intensely.
Should the above not work for you, invest in a pop filter- they're usually ~$5 and can increase audio quality by reducing the harshness of plosives. Some microphones have pop filters built in.
Turn your microphone gain relatively low. Then, turn the recorded track volume higher as needed in the audio editing program of your choice. This dramatically increases sound quality.
Recording with a blanket over your head (or perhaps in a closet) can reduce echo and reverberation.
Remember, what's best for me might not work best for you- always read customer reviews before making a purchase.