That is what Paul is concerned about, and wants Timothy to know: sound doctrine, and sound conduct. There will be those who will be led astray by other teachings, tempted by "demons", Paul says. He specifically refers to sects that prohibit marriage (ascetics) and who forbid certain kinds of foods, and practice all kinds of self-denial. So the sound teaching is that all things were created good and are to be used with thanksgiving to God.
As for sound conduct, Paul is very concerned that Timothy's church live in such a way that they don't give offense to the culture that surrounds them. So there's this extended conversation about widows, and who should be provided for, and who should not. (I have to ask, though: why are there so many widows, both young and old?)
Paul is also concerned about the reputations of leaders, and what makes a good leader. (this is a concern contemporary for us as well. There are leaders who lead their flocks astray, and cause offense today, by abuse of power, as well.) Paul is also concerned that a good leader be able to make a living without having to justify himself (it goes without saying that for this particular version of Paul, the leader is going to be a man.)
Finally, he calls Timothy to the high calling of leadership, and he exhorts him to hold firm in his faith: shun temptation, pursue righteousness, fight the good fight of faith. He reminds Timothy of the public confession of his faith that he made once (confirmation?) and to hold fast to this confession. He also reminds Timothy of another One who made a public confession before Pontius Pilate.
Paul reminds Timothy of the return of Christ, but somehow there does not seem to be the same urgency as in, say 1st Thessalonians. "The timing of this appearance is revealed by God alone," he says, as if to say, Jesus is delayed, but we don't know the day or hour, so let's be patient.
Patient. There was a sort of inpatience in Paul's early letters, a sort of leaning forward into the future. There's still a little of that (fight the good fight), but not quite as much impatience.
I miss the impatient Paul, who's always looking for the next mission field, crossing the next sea. He's impatient for the kingdom to come, for the reign of Christ to be manifest, for the lion to lie down with the lamb. He wants to see it.
Sometimes we can be too patient, and start wishing to just fit in.
Fight the good fight not to fit in.