A self-care checklist sounds formal, but it is really just a short list of small habits you want to repeat. Writing them down makes them easier to keep, especially on busy days when self-care is the first thing to get skipped.
Keep the list short. Five items is enough. A good starter list is: drink water through the day, wash your face gently morning and night, moisturize, wear sunscreen, and get to bed at a regular time. Nothing fancy, nothing expensive.
Tick items off as you do them. The small sense of completion helps the habits stick. After a few weeks, you will not need the list anymore, because the habits will run on their own.
Review the list once a month. Remove anything that never happens and add one new habit if you want. A checklist that grows too long gets ignored, so keep it short and honest.
Self-care is not a long routine or a set of products. It is a few small habits, repeated every day. A checklist just helps you remember them until they become automatic.
