Here are a couple of examples of the scoring system in action, taken from Ashley Wagner’s free skate routine at Nationals.
Wagner performed a “Level 3 Step Sequence” - that is, she pretty much “stepped across the ice,” and the official in charge of calling out the moves to the judges determined that it was Level 3 (out of 4). Each judge then gave it a grade from -3 to +3.
According to the Code of Points, the move is worth 1.2 (for a grade of -3), 1.9 (-2), 2.6 (-1), 3.3 (0), 3.8 (+1), 4.3 (+2), or 4.8 (+3). “Usually,” a +1 is for a move that has no errors but is otherwise “ordinary”; anything less than -1 is reserved for a fall or serious mistake.
The nine judges graded it 1, 1, 2, 2, 2, 2, 2, 2, 3; the high and low grades are thrown out, and the others converted to points (each 1 is 3.8 points; each 2 is 4.3) and averaged (4.23).
Just past the halfway point, she performed a triple loop - double Axel combination. Normally, a combination is scored as the sum of its separate moves; however, Wagner inserted something (probably a “half jump”, or what you might call a “zero Axel”) between the two that’s not listed in the Code of Points, so it was downgraded to a “sequence” and was penalized by 20% of the base (i.e. grade 0) score. On the other hand, it was after half of the 4-minute time limit had elapsed, so it was increased by 10% of the base score. (This rule rewards skaters who don’t do all of their best jumps early in the routine, before they get tired.)