Which are the guidelines for chose which cables should I twist as a pair? For example, suppose the case in which I have 3 cables. One of Vcc, one of GND and another of signal. Which ones should I twist? It would be better twisting signal+GND for better reference to signal (refereed to GND) or twisting GND+Vcc (for better decoupling)? Anyone may suggest good practices for twisting cables?
With an unbalanced signal i.e. signal and ground rather than + & - signal wires, twisting the signal and ground will just couple more ground-wire current into your signal (by magnetic coupling). If this 0V current is power taken by some unspecified load then it will create interference.
At best it won't make a difference. At worse you could create a lot of noise on the signal and maybe even damage something. Best way with single-ended signals is to use coax.