I like to use a liquid liner with a tapered brush applicator. I feel like it gives me more control and a more defined look.
Draw a line as thick as you want, fill it in, draw an angled line for the wing, another to connect it to the line on your lid and fill it in.
I know liquid liner can be sort of intimidating, but don't worry. Just take each step slowly and keep your hand steady. It takes practice!