☺☺☺☺☺I had visited the shrine in june 2015. Just like @qagiri has said,
The weather is very unpredictable it had started raining very heavily and then it was very cold.
Dont carry your mobile phone with you. Keep some cash, a water bottle and a blanket. This will help you get through security checks really quick.
Most importantly remember that it is not an easy trek if you are planning to do it by foot. 1 km on the mountain feels like seven. Your body will ache you will get very tired. It is a strength of stamina and will power. It is better to start practicing walking uphill and building your stamina before doing this yatra. Its better to ride a pony while climbing uphill and come down on foot.
One more thing, Get a place to stay either at bhawan or adhkawari. Booking needs to be done well in advance. I don't prefer climbing down the same day. Also if you aged people travelling with you then you definately need a stayover. I enjoyed the post @adsactly