Hear my prayer, O LORD, and give ear unto my cry; hold not Thy peace at my tears: for I am a stranger with Thee, and a sojourner, as all my fathers were. – Psalm 39:12

When thou art certain that the blessing sought for is a good and necessary thing for thy soul, then in order that thy spirit may be strong in prayer get a deep sense of it’s value, its goodness, and its necessity; examine it as a goldsmith inspects a jewel when he wishes to estimate its worth. A man’s ardour in pursuit will be in proportion to his consciousness of the value of that which he pursues. Get thou to feel what a precious thing grace is, what it cost the Lord to bring it to thee; what blessings it brings with it for time and for eternity, and when thy heart sees that it seeks after an unspeakably precious gift, then will its desire be stirred up to pray with intense longings.

Meditate much upon thy necessities that thou mayest get a sense of thy need of the mercy thou art seeking. See thy soul’s poverty and thine own undeservingness. Look at what will happen to thee unless this blessing come. If it be some absolutely indispensable spiritual blessing, picture to thyself where thou wilt be if God should withhold it, what evils will spring of thy continuing in want of it, and what further wants may yet beset thee. The more thy need smites thee the more eagerly wilt thou cry unto the Lord concerning it. Art thou desirous of bread for thy soul, be hungry, and let thine hunger eat into thy heart. Art thou desirous of the water of life; be thirsty, and let thy thirst burn thee till thou art dried up like a potsherd. Let thy necessities have liberty, by meditation, to seize thee and to distress thee with a sense of thine emptiness and nothingness…Get thou a consciousness of where and what thou art apart from Christ and from the mercy of God, and then, when thou perceivest well thy need, this, with a sense of the greatness of the blessing, will much quicken thee as to instancy in prayer. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1480.cfm