I’ve been on a bit of a mission since the beginning of Begin with Butter, to help people reach their personal baking zenith. It’s the central premise of BwB really to leave you a better baker than I found you (hopefully!).
1. Start with just the butter 2. Whether your butter was actually room temperature when you started; 3. The specific fat(s) and sugar(s); 4. How much butter and sugar you’re creaming together; 5. The equipment you’re using (because it will generally take longer with a hand mixer than a stand mixer); and 6. The speed of your equipment (I don’t run any mixer over speed 3 or 4 for creaming butter and sugar…there is literally no need to do that).