Driving with the flow and how NOT to get a speeding ticket.
Just my opinion: Driving with the flow is one of the biggest myths of the speeding-want-to-dodge-the-law crowd. While you are correct in the sense that driving with the flow helps you to "blend in" and therefore may result in fewer citations, it is just as true that an officer can only stop one vehicle at a time (usually). If you are solidly over a speed limit, no matter what the "flow" is, you can and will be cited if you are the ONE the officer focuses on -- you're just playing the odds.
Some folks can afford to get a ticket or two. If you want to avoid citations, keep your speed reasonable for the conditions, and no more than a few miles per hour over any limit when conditions are perfect (I don't travel more than 5-8 over, ever). Even then, you must accept the risk that you COULD be cited if an officer wants to make a point.
If you are in small towns, school zones or construction zones, adhere to the posted limit exactly. Also, in construction zones, make sure you don't resume your speed until you see a SIGN that states the normal speed limit is back in force -- sometimes this is quite a ways beyond the apparent end of the work, and it can be a prime area for an officer to lurk.
Finally, should you be cited for speed, it is essential (for your defense) to know the TYPE of speed law you've been cited for -- there are three, basically. Number one is "speed not reasonable and prudent" (this may be the most common speed ticket). This means that no matter what the posted limit is, if YOUR speed is not reasonable at that point in time and at that place, given the existing conditions, you are in violation. You might be able to argue that a slightly HIGHER speed was reasonable at the time and place you got the ticket -- and SOMETIMES you might win the argument, if you can prove your point in court.
The second kind is maximum speed posted on a highway. The law may read, for example, that the maximum speed allowed is 75 mph on any interstate highway. In practice, this is a SIGN violation, not a safety violation. You cannot argue that your speed was R&P given the excellent conditions and light traffic, for example. The officer is simply saying the sign said you could go 50, and you were going 57. End of story, unless you can show otherwise.
Finally, there are absolute speed limits, such as school zone limits, construction areas, etc. One (1) mph over, and you will be cited -- there is no grace and no tolerance. (These aren't really a different kind of law, but the enforcement is strict as a matter of policy.)
Different states may have differing versions of these types of laws, or as in my state, may use a combination of all of them. Let the lead-footed road warrior beware! :)