1. Pick an appropriate date
Halloween doesn't always fall on a weekend. It's up to you to select whether you want to have it the previous or the following weekend. Ask some of your VIPs when they will be most available and plan accordingly. Also, don't be afraid to have your party after Halloween...just because the day has passed doesn't mean you can't keep celebrating. This year, Halloween falls on a Wednesday and I'm sure your friends would be happy to come and celebrate with you on Nov 2nd or 3rd.
2. Invite your guests
Making a very nice, handwritten or handcrafted invitation to your Halloween party isn't even sort of necessary. Unless you're an extra crafty person, with a lot of time (and spooky supplies) on your hands, you can just skip straight to the internet. While there are plenty of quicker options, creating digital invitations is a nice idea. You can use them to show your party's theme and the format helps you focus on getting the details right. Of course, in order to do the digital invite, you'll need an email list...which you might not have. Alternatively, simply use a text message to invite your guests to the party. Make sure the data is final before inviting people.
3. Purchase or Make Decor
It's a good idea to purchase your decor a few days ahead of the party. Put up the decor the day before the party. You likely won't have time to decorate and cook on the same day.
4. Menu Planning
You will want keto friendly foods and drinks for your party. There are so many great recipes out there for people who are interested in this specialized diet. There's no need to skimp on treats...just make them keto friendly. If you're having adults at your party, make sure to research some keto friendly cocktails. This will be an awesome treat that your VIPs will look forward to. This might involve a good bit of planning. You'll want to find the perfect foods to serve - one that is both keto friendly and appropriate for the holiday.
5. Food prep & cooking
Prior to cooking, you'll want to plan out what to cook first. Begin by prepping the dishes that take longer to complete first, maybe even a day or two in advance. If you're using store-bought food, pick it up the day before the party and spend a few minutes plating/preparing when you get home. This will make it easier to jump into the party fun. There may be some foods you make the day of the event, but if you're smart, you'll pick dishes that you can prep a day or two in advance. Limit yourself to one "day of" dish...this will keep your party planning stress level super low.