Keep your cool! By this I mean work in a cool environment, or put the air conditioner on, and leave the oven off until the pastry is made.
Keep the ingredients cool. Take the fat out of the fridge before getting started, so that it has time to soften very slightly but not get runny. It is easier to rub into the flour if it is cool (but not rock hard).
Don't over work it. Use a light hand to rub the fat into the flour, keeping your hands up above the rim of the bowl to get as much air into the mixture as possible. Stop as soon as the two are combined.
Add the correct amount of cold water. The recipe will give you a guide as to how much ice cold water to add. You don't want to skimp and end up with a dry, crumbly shortcrust pastry which is difficult to handle, and likewise, you don't want to make it too wet so that it looses its shape while baking.
Roll it out on a cool surface. A marble pastry board
is perfection, but not too many of us can afford one of those I guess. So a good quality, spotless work surface will have to do, but try not to use an area that is in direct sunlight.
Stay cool. Chill the shortcrust pastry for 30 minutes after making it, before rolling it out.
Heat it up quickly. After emphasizing how important it is to keep everything cool, this one may surprise you. But when it comes time to cook your dish, you must ensure that the oven has been pre-heated to the required temperature. This sets the pastry in its correct shape straight away, and makes it easier to control the exact cooking time needed.