Goldreich-Goldwasser-Micali Construction
Levin showed that combining PRG with a universal hash function, one can reduce the number of calls. Roughly speaking, we shorten a message with a universal hash function before applying the GGM construction.
That is, $y = F_{k,k'}(x) = \mathrm{GGM}_G(k,h(k',x))$, where $h$ is a universal hash function.

At TCC 2012, Jain, Pietrzak, and Tentes gave another technique to reduce the number of calls with preserving hardness by using t-wise independent hash functions. See their paper for details.

Leonid A. Levin. One-way functions and pseudorandom generators. Combinatorica, 7(4):357-363, 1987. Levin87

Abhishek Jain, Krzysztof Pietrzak, Aris Tentes: Hardness Preserving Constructions of Pseudorandom Functions. TCC 2012: 369-382. JPT12