Section 1: Choosing the Right Yarn and Hook Before you start crocheting, it’s important to choose the right yarn and hook for your project. For doll outfits, you’ll want to use a lightweight yarn that won’t add bulk to the outfit. Cotton or acrylic yarns are great options. You’ll also want to use a small hook size, such as a 2.25mm or 2.50mm hook, to create the fine details needed for doll outfits.