Resistance primarily is 'how difficult it is for an electron to travel through a material'. When the electron travels through a material, it collides with ions which causes it to lose energy with each collision. The amount of energy lost by the electron in that length of the material is proprtional to the resistance. In the context of a wire, the resistance increases if the wire gets hotter or if it is replaced by a longer or thicker wire. If the wire is hotter, the ions in the metal vibrate more vigoursly, which cause more energy to be lost by the electrons. If it is longer or thicker, there are more ions for the electrons to collide with, so more collisions means more energy is lost. A visual analogy of resistance could be a school corridor scnenario. If a teacher (the electron) walks through an quiet corridor (low resistance wire), they can travel through the corridor quickly and with ease. If the corridor is now very busy with students (high resistance wire), the teacher may collide with some students on their journey, slowing the teacher down and requiring more effort to pass through.