I recommend an eyebrow razor.

This is a flamingo-shaped eyebrow razor purchased from Etude House. The blade is large and sharp, so it removes eyebrow hairs cleanly without much movement, and it doesn't dull easily even after prolonged use. I think I've had mine for about 7 years. Compared to traditional razors with smaller blades, this one is better for trimming the overall shape of the eyebrows.