It's all about fine lines and anti cat eyes. It can be really hard to get skinny eyeliner tough, it's fiddle and one twitch can muck the entire eye. I have two favourite products that I use to achieve the skinniest eyeliner possible, both are different types of eyeliner so there is something for everyone to use.
If you prefer crayon Chanel's Stylo Yeux Waterproof in Ebene* will help achieve very skinny lines. It is the best crayon I have ever owned, it lasts as long as any liquid liner and has a sharpener built in, which means you can easily sharpen it and get a neater line. It's perfect to use on both tom and bottom eyelids and is made from a lovely formula that doesn't feel to harsh on the eyes.
If you prefer a liquid Eyeko's Skinny Liner is a must. The nip is the perfect size to neatly draw just above and between the lashes. It's long lasting and it's also award winning. It doesn't smudge or fade and it's moisturising, it's pretty perfect...did I mention Alexa Chung uses it?