This tip applies to all stations across the globe. Stand next to the older gentleman in a suit who looks weary from a life of citybanking on the platform. He knows where the train doors will stop!
If you’re travelling on the Gatwick to Reading service and wish to travel forwards, the train doubles back on itself out of Redhill towards Reigate. It might be worth sitting backwards from Gatwick.
If the trains to Reigate are delayed there are always tons of cabs for abou £8. Don't try at about 4 pm though the roads get ridiculously crowded with the school run