Now that you have a fully stocked pantry with all the baking ingredients you need, it's time to plan your actual baking and do as much ahead of time as you can. Making things ahead of time alleviates stress and eliminates or minimizes wondering how you're going to get everything done in a compressed time frame.
First, plan what you're going to make. While I do a lot more baking during the holidays, I rarely try out new recipes unless I'm extremely confident they'll turn out. Because I have too much to bake and too little time so I can't afford to have a recipe experiment flop and leave me without anything to bring a party or give to friends at get-togethers. Experimentation is for the rest of the year. Holiday baking comes with a mission and nothing can jeopardize it. Besides which, oftentimes, my friends know I'm giving them a baked gift and have specific requests of their favorites which I'm happy to accommodate. After all, the gift is about the recipient, not the giver so my recipe has to be set aside during the holidays.
Second, once you know what you're going to make, do as much ahead of time as possible. Cookies are the best example. Make your cookie dough(s) ahead of time, portion them out into individual cookie-dough balls and put them in Ziploc freezer bags marked with the name, baking temp and time then place them in your freezer. Or roll the cookie dough into logs, wrap wax paper and saran wrap and freeze them for slicing later.
Some people like to bake the cookie dough first and freeze the baked cookies as their time saver. I have to admit, I'm not a fan of that. I'm a super stickler for freshness and to me, a freshly baked cookie is better than a freshly thawed cookie. Plus you don't have to worry about the cookies crumbling when you freeze, store and thaw them. Cookie dough, if it crumbles, can be squished back together before baking and no one will ever be able to tell once they're baked.
You also have to remember that once you give away your cookies, you don't know how long it takes your recipient to eat them so if you had baked them beforehand, froze them, thawed them then gave them away, that's a long life you expect the cookies to have and most cookies have a shorter freshness lifespan than that. It's better to freeze the dough and have it ready for last-minute baking and giving.
Cookie doughs that freeze well:
Alton Brown's chocolate chip cookies
Super Sugar Sparkles
Peanut Butter Fudge Cookies
Brown Butter Cookies
Brownies and bar cookies, on the other hand, (depending on the recipe), can easily be baked ahead of time and then frozen without their freshness being materially jeopardized.
What I like to do with brownies I'm giving away in individual care packages or gift bags is bake the brownies, let them cool, cut them into individual pieces then package them up, two squares to a package, wrapped in plastic wrap then put in freezer bags and stored in the freezer, marked with what kind of brownie they are. If I bake enough in advance, when it comes time to put together the gift bags or care packages, I have an assortment of brownies to choose from and give away. It's always nice for your recipients to get a variety. If I'm taking brownies to a party or potluck, after they've baked and cooled, I'll wrap the whole thing without cutting it and freeze it whole. When it's party time, I let it thaw then cut the brownies and arrange them on a nice plate. Unless you're going to wrap each individual piece, it's best to leave the brownies uncut so the edges don't dry out.
Almost all brownies freeze well - here are just couple of examples:
Peanut Butter Surprise Bars
Nutella Crunch Brownies
I rarely freeze cakes. The light, cakey texture I like in most of my cakes don't tend to freeze well or else if their flavor doesn't suffer from being frozen, sometimes their texture does. The only exceptions are pound cakes which are a dense enough texture to freeze well and basque cake. I love basque cake and I make them as individual-sized cakes which are the right size for giving away. If you do freeze cakes, please freeze them unfrosted (make the frosting at the last minute) and wrap the cakes well. Keep all frozen baked goods from odorous items in your freezer. Don't cozy up even your most well-wrapped baked goods next to that package of frozen fish or overripe bananas or else the odors and flavors could permeate your baked goods.