Thickness, length and temperature are the three factors understood to affect a material's property of resistance in conduction. These factors are also affected by the material in use, though this is accounted an independent influencing factor.
All metals have differing properties of conductivity. This makes some more suitable for use in conduction while others are inferior or even useless. The three factors influence these materials in a uniform way limited only by inherent conductivity.
Length is the literal physical length of the conducting element. The shorter the element, the better its conductivity as the electricity flowing through it has a shorter distance to travel and can thus travel at greater speed.
Width is the cross section of a given conductor. A wide cross section allows more electricity to move through the conductor at any given moment. More electricity means a more powerful current, and thus greater conductivity.
The final determining factor is temperature, which is more complicated. When a conductor is cold, electrons can move through it at high speeds. This is because the protons within the conductor are not moving, or if they are they are not moving quickly. A hot conductor's protons are bouncing around and interfering with electrons, leading to inferior conductivity and difficulties in completing circuits.