You didn't post what year your Rav4 is, but since you are posting in this section I will assume it is 2001-2003 like mine.
Each spark plug is covered by a coil pack/boot that is about six inches long and secured to the valve cover by a 10mm hex bolt. You need to remove at least the front half of the air box to have enough room to move around. Just remove the 4 bolts that hold the coil packs to the valve cover and pull each coil pack upward. They will pop off pretty easily. To remove the plugs you will need a 5/8" standard spark plug socket and a 6" socket extension.