If you like Ender's Game by Orson Scott Card

Since you enjoyed Ender's Game, you might want to try:

Damia's Children by Anne McCaffrey.
They inherited their mother's legendary powers of telepathy. But Damia's children will need more to face the enemy's children--an alien race more insect than human.

The House of the Scorpion by Nancy Farmer.
In a future where humans despise clones, Matt enjoys special status as the young clone of El Patron, the 142-year-old leader of a corrupt drug empire nestled between Mexico and the United States.

Starship Troopers by Robert Heinlein.
In this thrilling best-seller, [Heinlein] fast forwards to a
controversial future world where law and order are harshly enforced, and only the ex-military can gain citizenship.

Archangel by Sharon Shinn.
A dash of science fiction, a handful of fantasy, and a sprinkling of
suspense enliven the story of the Archangel Gabriel and his reluctant
wife Rachel.

The Book Thief by Markus Zusak.
Trying to make sense of the horrors of World War II, Death relates the story of Liesel--a young German girl whose book-stealing and
story-telling talents help sustain her family and the Jewish man they
are hiding, as well as their neighbors.