I tend to focus on long term sales, vs seasonal books. That said, the first 30 days after a book launch is critical to convincing Amazon that people want your books (or so people like me believe, I haven't seen any real data), so I tend to run freebies and $0.99 kindle sales, and promotions to email lists that cater to people interested in those things. I also start off the books at a low price, and raise them as the month goes on.

There are other people who focus on "low content" books like journals, log books, and children's activity books. They tend to more often do seasonal books.

I have done one "topical" book, about a new term that is trending on google over the last year, but it basically gets no sales. My mistake for not following the formula.