= Magical Realism
Borges is known well for using the technique of magical realism in his writing. For instance in his famous short story El Otro he is actually sitting on a bench next to his much younger self. They engage in a conversation and the technique of magical realism is used so well that it seems like it is actually credible.
= Metaphor
Borges is also well known for the usage of metaphors especially in the case once again of El Otro which is actually an extended metaphor of how he feels his life really and also how he feels most people's lives actually are. The fact is that most people evolve as they age in the way they think but traces remain of their youth and the way they used to think.
= Allusion
Borges as such an intelligent man would allude quite frequently in his writing to diverse things. For instance Borges alludes in La Muerte y La Brujula to religion when the plot is built around the tetragrammaton which is the four letter name of god which cannot be pronounced "YHVH". He also alludes to places that he has been like Argentina and Cambridge where he actually taught.
= Foreshadowing
As with all great writers Borges allows for a bit of foreshadowing in his writing especially as can be seen in La Muerte y La Brujula where the emminent death of the detective Eric Lonnrot can be noticed way before by his persistence in catching the murederer.