Most of the tips are absurd, but one is absolutely dangerous, and I will focus on that one here. NYT writes:
USE ONLY A DESIGNATED DEVICE Security experts suggest using a separate, designated device for sensitive communications. Of course, few things say philanderer, or meth dealer, for that matter, like a second cellphone.But the problem is greater than just having a second cellphone that you don't keep out of sight. Through casual reading it has become clear to me, though never divulged directly in an MSM article, that the government must have a method to determine who is using a second cellphone. I suspect they have the capability to track what I call parallel cell phone tower movements. If two cell phones are simultaneously hitting the same cellphone towers all the time, it is either two people travelling together, working together, etc. or one person with two cellphones. Monitoring the situation for 24 hours would in most cases identify, which is which.
Thus, carrying two cellphones will not defeat tracking done by anyone who has access to "parallel cellphone movement" data. This can only be defeated by keeping one cellphone off most of the time, the private cellphone. When a call from this phone is to be made, the regular cellphone should be left at home (or at the office) and the second cellphone should only be turned on and a call made when the private phone is far enough away so that a different cell tower picks up the signal and not the same one as the home (office) cellphone.
But, this will only help you against low level tracking methods, perhaps an infidelity investigation by a private detective. If you really are a spy, keeping the cellphone shut off won't help, I recall reading that a government in the Middle East (I forget which) tracked down some spy because they tracked cell phones that were only turned on for brief spurts, which is what he did.