Whether you are a seasoned sound mixer or a humble beginner just learning how to use sound effects, and production music, here are some tips and tricks for putting together the perfect audio track.
1. Good Sound Editing Begins With Good Recording
Make sure to use a recording device you are familiar with. Include about a second of silence both before and after recording a sound. This will help with mixing later on. Record close to the source of the sound with a directional mic for best results.
2. Use Trusted, Intuitive Software
Free software for simple audio editing projects is out there. Many computers also come with audio editing software pre-installed. If you have a Mac, look for a program called GarageBand. If you’re using a video editing program, you can usually edit audio within that program, too.
3. Set Your Volume Levels Carefully
Import all new sounds into your project at the zero level. This is the baseline. Once a few sounds are imported, you can adjust the levels of different tracks to create a spectrum of high to low level sounds. Always listen to your project with your computer volume set to a medium level, both with headphones and speakers. If something sounds too quiet or too loud, it likely needs to be adjusted.
4. Always Dissolve or Fade New Tracks
A new sound appearing out of nowhere is very jarring for the listener. Even a short fade-in can make it seem like the sound is entering more naturally. Use dissolves when one sound is leaving at the same time another is entering.  
5. Don’t Forget Room Tone and Background Noise
If you are creating an audio track for a scene, it won’t sound natural unless you include a recording from the space that the scene is taking place. It may seem silly to record what seems like silence in an empty space, but it is absolutely essential for setting a scene.
6. Apply Filters/Effects As Needed
In general, you should only add an effect to a sound when there is a clear source for the effect, otherwise it may come off as cheesy or disorienting. For example, if a character is walking through a tunnel, you can add reverb to the footsteps. You can also add filters to recorded voices to differentiate voice-over narration or a voice on the phone from regular dialogue.
7. Use Sound Databases for Royalty-Free Clips and Music
Online resources like Storyblocks are great places to find high-quality sounds that you aren’t able to record yourself. Just subscribe and download all the sounds you could ever need!