The Letters of Peter, James, John and Jude are called by scholars the "catholic" epistles -- because they don't seem to be written to any one church (as Paul's letters were) but seemed meant to be shared among many churches. So they are not known by who they are to, but by who (supposedly) wrote them. I say supposedly because not all scholars are agreed that every one of these catholic epistles was written by the person to whom it is ascribed.
Aside: the word catholic means "universal."
That being said, there does seem to be a theme for this short letter. It is written to a church, or to churches, that are experiencing persecution. So there is a combination of inspiration, encouragement and exhortation in this letter. There's the wonderful image of the church as living stones, chosen, gathered up and built into a house by God. Peter wants the people to remember that God first loved and chose them; this will help them to resist the temptations they encounter and the sufferings that they need to endure. He identifies the people as strangers among people with different values than their own. He encourages them to continue to live counter-cultural lives, resisting finery, and living simply. Persecution and suffering naturally come to those who are faithful (look at Jesus, after all).
I have to admit some discomfort with some of the author's advice, especially his advice to slaves to obey their masters and just keep taking the abuse. Although this was certainly written at a different time than ours, when the Roman empire did not take kindly to civil disobedience, these verses and others have been used to justify oppression and slavery. And do we want to counsel women to put up with being beaten by abusive husbands, because suffering can be good for you?
We need to be careful how we read scripture.
Certainly there is truth here. We can't avoid suffering in life. And it's true that many have suffered for good cause, and that good has come out of it (I think of those who peacefully protested the Jim Crow laws in the south, and won civil rights for themselves by their faithful witness).
So the author writes to people who are experiencing suffering, and we can hold on to this: suffering is not good, but when we encounter suffering in this life, it also does not that we have done wrong. Sometimes it is a price we pay for doing the right thing.