As the holiday season nears, if you are in the U.S and your primary audience is North American then you will see a decline in the number of people who visit your blog. I am sure you know what the reason is, people are busy doing other things.
There is not much you can do about dip in blog traffic then to keep blogging with some regularity. You can also do what I am doing this month, slowing down a bit. It is a good time to reflect at the year that was 2009 and see if you can do things differently next year.
I started this particular blog in September and I have experimented with few posts and have been able to understand my audience. I will soon plan out an entire list of goals I would like to achieve next year. Keep and eye out for that and make sure you follow my lead.
Dip in blog traffic is a cyclical event that is predictable every year. Make something out of it by reflecting and learning. Excellent time to listen and generate more ideas.