I put "privacy" in quotes, because under the scheme below you're still giving up a lot of data, but you can (I think) still maintain "silos" of data so that, for example, your search data isn't correlated with your YouTube or GMail data.
- In Firefox, I've installed Ghostery. This blocks all kinds of trackers, including Google Analytics.
- I've switched from using the GMail web UI to a desktop client. Google still sees all my email, but I don't have to remain logged in to that account in the browser. (See #4.) This effectively makes the mail account a silo; none of the data is used elsewhere. I occasionally have the fantasy that I'm going to move my domain off Google Apps and go back to self-hosting, but that's unlikely to happen in the near future.
- When I'm browsing, I'm logged into a second Google account that is disconnected from my primary mail account. (See #3.) This means that, for example, videos that I watch on YouTube aren't correlated to the content of my mail.
- In Firefox, I've installed Adblock Plus. This cuts down on tons of ads; which might avoid leaking your data to advertisers.
- I haven't done it yet, but I plan to find a desktop RSS reader that doesn't suck and delete everything from Google Reader.
- I've stopped checking in at Google News. Instead I pick one of CNN, News360, BBC, or other news outlet.
- I'm not sure what it would be, but if I'm browsing stuff that I don't want tracked, I'll fire up a Chrome Incognito session and proxy everything through Tor. (The only reason for using Chrome is that I typically don't want to interrupt a Firefox session to drop into Private Browsing mode there.)
It's worth noting that I don't use G+, so I'm not doing anything specific to maintain a silo there.
As noted above, most of this doesn't vastly enhance your privacy. You're still handing out a lot of data every time you browse the web; it's a fact of life. And it is, after all, very convenient to have access to your search history -- I often find myself trying to figure out what that thing was that I found during a search a couple of weeks ago but can't remember the terms I used. But I'm hoping that it cuts down on the amount of data correlation between my various online activities.