An eyebrow pencil such as this one lets you experiment and play with the shape of your eyebrows and get them just right. This product is waterproof, which is very handy during summer.
From Debenhams
Precisely My Brow Pencil Ultra Fine Shape & Define Mini 0.04g - 4. Warm Deep Brown - One Size
House of Fraser
Benefit Precisely My Brow Ultra Fine Brow Pencil Mini - Brown