Article taken with thanks from http://central-mosque.com/index.php/Acts-of-Worship/istinjaa-wudhu-tayammum-a-ghusl.html
Sunnah actions of Wudhu (Sunan):
1 Make intention at the beginning
2 Reciting of Bismillah
3 Washing the hands up to the wrists three times
4 Brushing the teeth with Miswak
5 Gargling three times
6 Passing water into the nostrils three times
7 Khilal of the Beard i.e. to pass wet fingers through the beard
8 Khilal of the fingers and toes
9 Washing each part at least three times
10 Masah of the whole head once
11 Masah of both ears once
12 Wudhu performed systematically (in order)
13 Wudhu performed continuously and parts washed one after another without pausing so no part dries up before the next is washed
Desirable actions of Wudhu (Mustahabaat):
1 To begin from the right
2 To make Masah of the nape
3 Not to take assistance from anyone
4 To face the Qiblah
5 To sit on a high and clean place
Undesirable actions of Wudhu (Makroohat):
1 To make Wudhu in a dirty place
2 To clean the nose with the right hand
3 To talk of worldly affairs
4 To perform Wudhu against the Sunnah
Nawaaqidh (Nullifiers) of Wudhu
1 Discharging of Urine, Stool or the coming out of anything from the Private Parts.
2 Discharging of Gases.
3 Vomiting Mouthful.
4 To fall ASLEEP lying down or by resting the body against something.
5 To FAINT due to some illness or any other reason.
6 Becoming Insane or going Mad.
7 Laughing loudly during Salah (Paryers)
8 Flowing blood or matter from any part of the body.