Lots of good technical advice has been given and I won't rehash that, but I think there are lots of other methods you'll need to consider, too.
1) Time of publish. You'll want to make sure the times you publish entries are random and can't be correlated with things you are doing. If you take a vacation, you'll need entries going up.
2) How you write. You'll want to ensure your writing isn't too similar to your own. Either have others write it, excessively use synonym dictionaries, or introduce writing styles and elements exclusively to the posts you write.
3) What you write about. It should be as diverse as possible. If you only write about one topic, or clearly have a bias for one topic, then it is easier to pin down your interests and focus searches against you to that. Write about cooking, about programming, about art, about politics, etc. Even if you hate or aren't good at it.
4) Fabricate entries. You'll want to write about topics you dislike, or topics you don't believe in or about places you have never been. Reference dates and times that would be impossible with your schedule, your income, your skills, or your connections. For areas you are most versed in, introduce simple errors to reduce your apparent expertise. In areas you are most ignorant, plagiarize from experts in a non-obvious way to fake expertise.
5) Write in only your native language so as to not giveaway where you learned some other language. If this isn't enough, then run your writing through an automatic translator each time into some other language you might know and only do a light touch up of the most egregious errors.
You kind of get the drift. Lots of people here can give technical advice, but that is always one slip-up from going wrong and you getting caught. Having lots of disinformation and mixed information in the blog itself can help provide cover and deniability.