It takes long and one has to persist. Few things which will help are.
1. To step back before reacting to people or situations. Make it a habit not to act without reflection and in that little pause remember the Mother.
2. Whenever mind grows restless give it an interesting subject or work.
3. Stay busy and do lot of exercises to circulate the vital energies.
4. Stay away from activities that cause restlessness and excitement.
5. Call peace, calm, equanimity as often as you can until peace becomes your friend.
6. Analyse and reflect upon what causes restlessness and work upon those aspects.
7. Most importantly call Her as often as you can and ask for Her Grace.
Affectionately,
Alok Da