[majormjr]

Good lighting makes a big difference as well, even low quality webcams on laptops look much better if your face is well lit.

[minimaxir]

Ring lights help in this area as well and are cheap enough nowadays.

[handrous]

Thanks to ring lights and Youtube, I'm pretty sure my kids are going to grow up thinking there's some variety of eye-color that features a bright white ring in the center of the pupil.

[Scoundreller]

Or a desk lamp pointed at the wall behind your laptop if you’re at a desk.

[maaneeack]

Several times I've opened a white page full screen on my monitor while doing an interview via Phone or Laptop. That plus the over head light being on but not being in the view helped quite a bit.