Gently ease the pastry into the tin, pressing it down the sides onto the base.
Once you have pushed it in all the way round, go around again to press well down on to base, so that there is almost a 'pleat' of pastry at base of sides, and press into the flutes.
Fold back excess pastry so that it hangs over the sides of the tin.
To cut off the excess pastry roll the pin firmly over the top of the tin in both directions.
Gently pull away excess pastry.
Now gently pull up the sides of the pastry from the small excess you left at base so that the pastry stands slightly proud of the top. This will ensure a good depth to the sides of the flan if the pastry shrinks slightly in cooking.