I started teaching my boy once he showed interst in pens & pencils. Taught him to hold properly first and allowed him to doodle. Then let him do tracing of pictures and colouring. around 2.5yo he started to write alphabets & numbers through observation although some strokes are incorrect. Then we started to show him the correct strokes. He can write all alphabets now in small & caps. Can write number 0-9. but handwriting not very neat but good enough. He just turned 3yo 2 wks ago.