You will need:
The shadow tip method works by knowing that the Sun travels across the sky from East to West everyday, and that at some point in time the Sun has to reach it's highest point of travel , i.e. midday. Midday time is different at every point on the Earth's surface, so finding true north requires you to take a measurement at the location in which you are standing.
Midday time on your watch will be different to midday time found by the shadow method.
Towns and cities have been placed in 'time zones' so that people in a 'time zone' all operate off the same time. If your town is in the middle of a time zone your shadow method would have found midday to be very similar. However if your town is on the edge of a time zone, your midday found by the shadow method may be quite different.
How can you find South using a constellation in the Southern Hemisphere?
1) Have a look up tonight and find Crux (the Southern cross). Draw an imaginary line from the top of the cross, through the bottom of the cross and keep going downwards towards the horizon.
2) Look to the west and you will see two bright stars called the Pointers. Draw an imaginary line between these two stars. Find the mid-point between the Pointers on this line and then draw a perpendicular line towards the horizon.
3) Where the line from Crux meets the line from the Pointers draw an imaginary line straight down to the horizon. You've found the direction for the South Celestial Pole.