With prepositional clause:

Yo te doy el libro [a ti: redundant/emphasis]
I give the book to you

(Tú) Le das el libro a Pedro
You give the book to Pedro

No prepositional clause:

Yo te doy el libro
I give you the book.

(Tú) Le das el libro
You give him the book [incorrect to express a prepositional clause]

Using the Direct and Indirect Object Pronouns at the Same Time

(Yo) te doy el libro [a ti] - I give the book to you
(Yo) te lo doy - I give it to you [I give you it]
(Nosotros) les damos el libro a las niñas - We give the book to the girls
(Nosotros) se lo damos - We give it to them