Keep your eye half-open so that you can more easily follow the eye's contours. Try getting your line as close to the lash line as possible by lifting your eyelid from under the arch of your eyebrow instead of tugging the skin off to the side, as is common practice. When you're just starting out, don't worry about doing the line all in one go. Draw three fine dashes, one on the inside, middle, and outside corner, and connect them.