First Timothy 1-6, Second Timothy 1-4, Titus 1-3, Philemon

First Letter of Paul to Timothy is, as it suggests, a letter from Paul to his favorite associate.  He's asking Timothy to remain in Ephesus.  He also warns about dissenting ministries, explains his past. Paul also outlines a number of guidelines for the emerging Church, including rules for the selection of bishops of deacons.  It's more or less a set of instructions to keep on keeping on.

Second Letter of Paul to Timothy finds Paul missing Timothy.  He's hit a rough patch.  The ministries in Asia have been less than accommodating.  He tells Timothy not to be ashamed of testifying and to accept suffering, which might just as well be Paul telling these things to himself, which in effect makes this perhaps the most personal of all the letters.  Titus, Luke, and Mark are all referenced.

Letter of Paul to Titus, meanwhile, is obviously another personal address to a notable colleague.  He's explaining why Titus was left in Crete, and how best to deal with the Cretans, which probably explains why we have that term today.  Which means in honor of this letter, if you hadn't been using it before, you should now (but in a loving way).

Letter of Paul to Philemon is the last one directly ascribed to Paul in the New Testament.  He's once again a prisoner as he's composing it.  Timothy is referenced.  He's basically directing matters from prison.  Mark and Luke are also referenced.

Colossians 1-4, First Thessalonians 1-5, Second Thessalonians 1-3

The seventh letter from, the Letter to the Colossians, features a reference to Timothy right from the start.  It explains what exactly Jesus represented, warns about falling for dissenting beliefs.  Perhaps the biggest news out of this letter also explains something from Acts.  Remember how Paul and Barnabas had a falling out over Mark?  According to this letter, Barnabas had a good reason to side with Mark, because the possible gospel writer was in fact his cousin.  Another probably gospel (and Acts) writer, Luke is referenced, as "the beloved physician."  Considering how often Paul is described as getting banged up in Acts, he could certainly use one of those.  The letter concludes with a message to pass it along.  And passed along it has been.

First Letter of Paul to the Thessalonians references Timothy right away.  These Thessalonians are also excellent examples of the faith.  Paul references his rough treatment in Philippi, which otherwise didn't deter him there, because that's the other community to get a happy letter from him.

Second Letter of Paul to the Thessalonians also references Timothy immediately (it should be noted that when this happens, it means Paul has included him in the opening address, so these letters can be said to be coming from both of them).  Paul is still very pleased with the Thessalonians.  He likes them so much he uses them as an example to other communities (and thanks to this letter's presence in the New Testament, keeps on doing it).  Both letters speak of the second coming, which is an event preceded by the Antichrist.  You can take that literally or interpret it to indicate the persecution from the Roman Empire, which certainly got pretty nasty.