Want your shots to pop just a little more? This is something I do all the time, especially with interviews or any time my subject isn't moving around much. And it's all built right into Final Cut.
Shape the light with a mask
Start with your shot already corrected and graded. Open your color wheels (or color board), hit the little mask icon, and add a shape mask. Draw a long, elongated oval and place it over your subject. That outer circle is your feathering, so nudge it to make your adjustments nice and gradual.
With inside selected, raise the exposure on your highlights a touch. I go for the highlights and not the midtones because pushing the midtones tends to wash your subject out. Then click outside and pull the midtones down a bit, and drop the shadows slightly if you want. Just don't crush your blacks below 0 on the luma waveform, or you'll lose detail in the darkest parts of the image.
If you hit view masks and select color, you can see exactly what the inside of the mask is affecting. Now toggle the effect on and off, and honestly, it looks like you added a whole new lighting setup back on set. It makes a big difference in how much your subject pops. I do this in every single talking-head portion of my YouTube videos.
Fake a shallow depth of field
Here's a bonus. Add a focus blur to your clip and drop the height so it covers the full image. Create a shape mask again, open the little drop-down and hit invert, then place the shape over your subject and feather it down a bit. Boom, you've got a fake shallow depth of field. It's not perfect, but it really helps smooth over a busy background.
You can do the exact same thing with the sharpen effect, except this time don't invert it, so you're sharpening your subject instead of the background. A few simple steps and you've gone from a flat shot to one where your subject really separates from the frame.
Master light, color, and attention
The FCP Color Grading Masterclass goes deep on shaping light, directing the viewer's eye, and building professional grades from scratch. Featured on Apple's official Final Cut Pro Resources page.
Explore the Masterclass