Devour old films, new films, music, books, painting, photographs, poems, freams, random conversations, architecture, bidges, street signs, trees, clouds,bodies of water, light and shadows.
Select only things to steal from that speak directly to your spirit.
If you do this, your work (and theft) will be authentic.
Authenticity is invaluable; originality is non-existent.
And don't bother consealing your thievery -celebrate it if you like it.
In any case, always remember what Jean-Luc Godard said: "it's not where you take things from -it's where you take things to."