Odysseus made his first mistake with Polyphemus, the cyclops. He should never have boasted his name and bragged of his accomplishment. That was what got him into so much trouble with Poseidon.
Then when he was on his way home with the bag of winds, he should have told his crew what he had. Instead, the mystery ate at his men, and thinking it was treasure, they opened it. This sent them way off course where they encountered more troubles yet.
When in the Land of the Dead he learned that he should make sure his wife is loyal before trusting her completely. He learned that from the dead Agamemnon.
When he passed through Scylla and Charybdis, he had to inspire his men, knowing that 6 would die. He went anyway and knew is was part of his punishment. It was the only way home. He then knew that he would be the only one to return, but he tried to save his men anyway. He learned overall that he must obey the gods and sacrifice to them for his wrong doings.
In Homer's Odyssey, Odysseus' first stop after leaving Troy is the land of the Cicones. After initially defeating the Cicones in battle, the Cicones regroup and attack Odysseus and his men, who had gotten a bit drunk after their initial victory. I would suggest that in this encounter Odysseus learns that he should not assume that after someone has been defeated once that they will remain defeated.
Odysseus' next stop is the land of the Lotus-Eaters, who offer some of his crew a food that causes them to forget about their desire to return home. In this encounter, both Odysseus and Homer's audience learn to focus on what is important in life. In Odysseus' case, coming home is paramount.
Because troutmiller has already covered the encounters with the Cyclops, Aeolus, and Scylla, I shall turn to the Odysseus' encounter with the Laestrygonians, which apparently results in Odysseus' worst losses (eleven of his twelve ships are destroyed). As in the case of the encounter with Polyphemus, it appears that Odysseus' curiosity gets him in trouble: "I sent a party of my men to find out what sort of beings lived there" (Kline translation).
We should also note Odysseus' encounter with Circe. Odysseus spends a year with Circe and once again the concept of homecoming is reinforced. In contrast to the land of the Lotus-Eaters, where Odysseus had to drag some of his crew back to the ship, on Circe's island it is Odysseus' crew who have to remind their commander to "remember your native country" (Kline translation).
Finally, we cannot omit Odysseus' stay with Calypso, which takes up seven of the ten years of Odysseus' return voyage. Again, Odysseus thinks of homecoming. Even though Calypso offers him immortality, Odysseus realizes that "life’s sweetness [was] ebbing from him in longing for his home" (Kline translation).
Ultimately, Odysseus learns that the best place for him to be is where is wife and family are: at home on Ithaca.