place a 10 pence coin (or equivalent in local currency) on your head. balance it there all day. keep it there until you forget about it. (purest will resist, but it is permissable to use adhesive).
repeat daily until mastered.
once mastered add another 10 pence coin. again, repeat until mastered.
and so on. until the coins reach 1 metre high (or £99.90 – keep below £100 for insurance reasons).
let me know how you get on.
[an interesting twist on this game is to use only coins which have been found lying in the street – this way the values, sizes and days when additional coins must be added is an additional variable to consider]
(based on an idea from the Fluxus movement)