How to closeness to Allah

The Ahlullah have mentioned two secrets to gain the closeness to Allah. 1. Dhikr in isolation. 2. Tahajjud. Mufti Ebrahim Desai Saheb has expounded on this in the light of Quran and Hadeeth. He emphacized on the importance of Tahajjud, especially now that it is winter and the nights are long.