1. Christmas Tree: A well-decorated Christmas tree is the centerpiece of any holiday decoration. Choose a fresh, fragrant fir or pine tree or go for an eco-friendly artificial one.

2. Decorations: Think about the decorations you will use for the tree as well as throughout the house. This can include ornaments, garlands, wreaths, candles, lights, etc.

3. Gifts: Start brainstorming what gifts to buy for family, friends, and colleagues.

4. Wrapping Supplies: Purchase festive gift wraps, bags, boxes, ribbons, tags, and tape.

5. Festive Clothing: Plan out what you will wear on the day itself. A new festive sweater, party outfit or pair of cozy PJs would be ideal.

6. Holiday Food and Drinks: Make a list of groceries and drinks you will need for holiday meals, parties, and cozy winter evenings at home.

7. Advent Calendar: It can be a traditional chocolate one for kids, or something more grown-up like a beauty, tea or even a wine advent calendar.

8. Christmas Cards: To send season's greetings to your friends and family who live far away.

9. Stockings: You will need these to put all the stocking stuffers in.

10. Stocking Stuffers: These are usually smaller, less expensive gifts.

11. Baking Supplies: If you're planning to do a lot of holiday baking, make sure you're well-stocked with necessary ingredients and baking tools.

12. Holiday Movies or Books: To get in the festive mood.

13. Christmas Crackers: A tradition in many families, these add a fun element to the Christmas dinner table.

14. Tech Gadgets: Electronics are often on sale around Christmas time.

15. Toys: Particularly for younger children, a big part of the holiday is waking up to new toys under the tree.

Remember to plan and shop ahead to avoid the last-minute rush, keep an eye out for holiday sales and discounts, and most importantly, buy things that add joy to the holiday season.