In order to level the Skill faster, try to always cook while Inspired, and cook the highest level dishes. Sims with the Creative Trait will get random Inspired Moodlets, and those with the Foodie Trait can watch Cooking Show for Ideas or Search for Recipe Ideas on the Computer (found under Web). An easy way for Sims to get Inspired is to take a Thoughtful Shower or Browse Art from the Computer. To learn how to get Inspired, see the page on Inspired or Emotions Guides.
Being Inspired will not only help you level the Skill faster, it also increases the likelihood your Food will be made in Excellent Quality, which is the highest quality in The Sims 4. Both Cooking and Gourmet Cooking are Creative Skills, therefore their Ideal Mood is Inspired.
