Paul started pretty much all his letters with something like "Paul, follower of Jesus Christ, to all the saints in ________ (fill in the blank, Rome, Corinth, Ephesus, the Church in Philippi, etc.)" These letters are written to the churches, which are made up of Christians. He further says that they are called to be holy. A saint is a holy person. Holy means sacred or set apart. Paul is writing these letters to churches, reminding the Christians that they are set apart by God (holy) to reject the ways of the world and follow the ways of God. Peter, in 1 Peter 2:5, tell Christians that they are a holy priesthood, which is along the same lines as what Paul is telling people.
Angels in the Bible have done things like guard the garden of Eden after Adam and Eve got kicked out, cared for Jesus in the wilderness (Matt 4:11), freed apostles from prison, sent messages from God to people, warned people of danger, opposed Satan, etc. As far as I can figure, they are beings who do the biddings of God. They are present in heaven, as seen in Revelation, and they are higher than humans, because in Hebrews 2, when it's talking about Jesus becoming human, it says he was "made a little lower than the angels." That makes me think that humans are lower than angels.
But neither saints nor angels should be worshiped. Deuteronomy 6:13 (echoed in Matt. 4:10 and Luke 4:8) say "worship the Lord your God and serve Him only."

