What do I have to do to achieve crispy pastry on my pies?

Blind baking is the answer. What is blind baking?

It is the process of baking the pastry before putting the filling in it.

After placing the pastry to mould to its dish or pie tin, line it with baking paper and weigh it down with dry rice or beans.

The pastry is then baked at 180ᵒC for 15 minutes until the edges turn slightly brown.

Remove the baking paper and beans/rice. Return the pastry to the oven to bake for 15 minutes more.

Only then, can the filling be poured into the pie and immediately baked.