"When my servants ask you concerning me, (tell them) I am indeed close (to them). I listen to the prayer of every suppliant when he calls on me." [2:186]
Our Beloved Prophet, peace and blessings be upon him said:
"Nothing is more honorable to Allah the Most High than dua." [Sahih al-Jami` no.5268]
"The most excellent worship is dua." [Sahih Al-Jami` no. 1133].
Dua is so powerful that when we make dua, it can change our fate as Allah, the Most High, grants what He believes is best for us as He knows the Unseen. He answers each person in need and every request. The manner in how we make dua should be done with utmost respect and sincerity. We should never give up dua nor should we lose hope in Allah’s blessings and mercy. For Allah is the Most Generous so never put in mind that He will not grant your request.
Our Beloved Prophet peace and blessings be upon him said
"Verily your Lord is the One modest and Generous, and when His servant raises his hands to Him in supplication, He is diffident (in some wordings, shy or hesitant) from returning them empty." [Ahmad, Abu Dawud and at-Tirmidhi - Hasan]
Making dua is a recognition of our weakness and His power and greatness.
"O mankind! It is you who stand in need of Allah, but Allah is Rich (Free of all wants and needs), Worthy of All Praise." [Quran 35:15]
Our Beloved Prophet peace and blessings be upon him said:
"Ask Allah for everything, even the lace of your shoes. If Allah does not provide, it will never be available."
[Ibn al-Sunni, no. 349 - hasan. Supported by at-Tirmidhi 4/298 and others.]
Always remember that efforts with Dua changes everything.