Even if you don't make tutorials, I think you'll find these audio tips useful for whatever you create. As viewers, we subconsciously expect to hear something when we see something happen on screen, so let's hop into Final Cut and go over my "secrets" (finger quotes).
Solo select and nudge into place
When I find a sound that matches the visuals, the first thing I do is solo select it so I'm not distracted by the dialogue, music, and other effects in the mix. The default shortcut is Option S, but I've mapped mine to the C key. With it soloed, I use period and comma to nudge the sound a frame at a time until it lines up exactly with what's on screen.
Re-time the sound to fit the visuals
Sometimes a sound runs longer than what's happening on screen, you wouldn't hear a long drawn-out whoosh after a transition already stopped moving. So I re-time it: hit Command R and drag the sound effect until what you hear matches the duration of what you see, nudging with period and comma to lock it in. By default Final Cut preserves the pitch when you change the duration, so it won't sound higher or lower, but if you do want the pitch to shift, just toggle that off.
Dial volume in precisely
If you're annoyed at how easily you blow past the volume you want when dragging, hold Command while you drag and it makes much finer adjustments. You can also press Control Option L to type in the exact decibel you want.
Vary the pitch so sounds don't get stale
If I've used a sound effect recently in the edit, I'll drag the Pitch effect onto it and shift it slightly. Hearing the exact same sound over and over gets noticed and becomes a distraction, so a little pitch novelty keeps your viewer engaged.
Pan it to match the movement on screen
This is a big one for me. I use the stereo left/right pan mode to make a sound feel like it's coming from a specific direction. Say a pop-up flies in from off-frame left and lands in the center: I go to the start of the sound, slide the pan all the way left, and hit the keyframe button. Then I find the point where the pop-up reaches center and stops, and drag the pan slider back to the middle. Because I keyframed the start, that move saves automatically, and now the sound feels animated right along with the visuals.
Great audio deserves great color
Clean sound gets viewers to stay. Polished color gets them to trust what they're watching. The FCP Color Grading Masterclass teaches the complete professional color workflow, featured on Apple's official Final Cut Pro Resources page.
Explore the Masterclass