The Lord's Prayer is our model
"This, then, is how you should pray: "‘Our Father in heaven, hallowed be your name, your kingdom come, your will be done on earth as it is in heaven. Give us today our daily bread. Forgive us our debts, as we also have forgiven our debtors. And lead us not into temptation, but deliver us from the evil one" (Matthew 6:9-13).
We can approach God boldly through Jesus, our high priest, who understands our needs
"Therefore, since we have a great high priest who has gone through the heavens, Jesus the Son of God, let us hold firmly to the faith we profess. For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet was without sin. Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need" (Hebrews 4:14-16).
Pray continually and give thanks in all circumstances
"...pray continually; give thanks in all circumstances, for this is God’s will for you in Christ Jesus" (1 Thessalonians 5:17-18).
Pray in faith
"But when he asks, he must believe and not doubt, because he who doubts is like a wave of the sea, blown and tossed by the wind" (James 1:6).
"Have faith in God," Jesus answered. "I tell you the truth, if anyone says to this mountain, ‘Go, throw yourself into the sea,’ and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours" (Mark 11:22-24).
In time of sickness, pray
"Is any one of you sick? He should call the elders of the church to pray over him and anoint him with oil in the name of the Lord. And the prayer offered in faith will make the sick person well; the Lord will raise him up. If he has sinned, he will be forgiven. Therefore confess your sins to each other and pray for each other so that you may be healed. The prayer of a righteous man is powerful and effective" (James 5:14-16).
"Hezekiah turned his face to the wall and prayed to the LORD, "Remember, O LORD, how I have walked before you faithfully and with wholehearted devotion and have done what is good in your eyes." And Hezekiah wept bitterly. Then the word of the LORD came to Isaiah: "Go and tell Hezekiah, ‘This is what the LORD, the God of your father David, says: I have heard your prayer and seen your tears; I will add fifteen years to your life. And I will deliver you and this city from the hand of the king of Assyria. I will defend this city" (Isaiah 38:2-6).
Dare to pray for great things, as did Elijah
"Elijah was a man just like us. He prayed earnestly that it would not rain, and it did not rain on the land for three and a half years. Again he prayed, and the heavens gave rain, and the earth produced its crops" (James 5:17-18).
God hears and answers prayer; He is near to His children
"The eyes of the LORD are on the righteous and his ears are attentive to their cry; the face of the LORD is against those who do evil, to cut off the memory of them from the earth. The righteous cry out, and the LORD hears them; he delivers them from all their troubles. The LORD is close to the brokenhearted and saves those who are crushed in spirit" (Psalm 34:15-18).