There’s a reason filling in brows is a non-negotiable for makeup artists. The process puts the finishing touch on tons of different types of looks, from no-makeup makeup to full-glam moments, and great eyebrows help highlight your facial features. For the brows alone, it can define their shape, disguise sparse spots with pigment and even fix unfortunate tweezer mishaps. (Raise your hand if you’ve been there!)While filling in your brows isn’t necessarily a difficult task, it’s not quite as simple as drawing on some faux hairs and calling it a day. So, to get a clear and concise breakdown on the technique, we reached out to Sarah Biggers-Stewart, a professional makeup artist and the founder and CEO of CLOVE + HALLOW. Read on for her tips on the types of products you’ll need on hand, plus exactly how to fill in your brows.