One important way is that Virgil deliberately imitates Homer. It has often been stated that the first six books of the Aeneid are Virgil's Odyssey and the last six books are Virgil's Iliad.
The first six books of the Aeneid are about Aeneas' voyages, being delayed by a woman, and a descent to the underworld--definitely reminiscent of Odysseus' journeys. They even meet some of the same characters (such as the Cyclops). An important difference is that while Odysseus is trying to get home, Aeneas learns he is to establish a new home for himself and his people.
Just as the Iliad is mainly about war, the last six books of the Aeneid are about the battles Aeneas fights to establish his people in Italy. This part, and thus the epic, ends on a very abrupt note just as the Iliad does.
Much more could be said about "shaping the text," but the parallels with Homer are as good a place as any to start.