Don't leave it for the last minute. Make the page early so that Google bot has time to crawl it. Make sure the page(s) are crawl-able.
Take benefit of landing page SEO practices
Put links to Cyber Monday and Black Friday pages on your home page for easy find. Both for visitors and Google
Do not use a new URL if the events happens more than once. Use a reccurring URL
Use a high quality, static image with no white space which talks about your deal. You can read about the best image practices here
Check your page's structured data and ask Google to recrawl the page
Good luck, make interesting offers to your customers. I might land up on one of your offers and take benefit of it. 😉
Give enough time to crawl. That seems more important to me than everything else. A bad listing is better than no listing.
I agree. Don't keep it for the last minute. But some webmasters will believe that their offers will be exposed too soon through Google search if they put it out early enough.
Definitely need to leave adequate time for crawling. The listing is useless if nobody can find it.