How can I be more
confident in prayer?

You first need to believe God exists, and then you need to believe He rewards those that diligently seek Him (Heb 11:6). Claim His promises about prayer – He wants you to trust Him in this special privilege to access His powerful help in your life. He is vulnerable to your prayers, like allowing Jacob to win their wrestling match! He has promised to hear and answer your prayers, and the Bible is filled with powerful examples of prayers that were answered in every part of life. He encourages prayer, enhances your prayers, and can easily exceed your requests.

See Also

For a summary of encouragement in prayer: Confidence in Prayer.
For sermon outline examples of powerful prayer: Power of Prayer.
For slides from Bible study about power in prayer: Power of Prayer-II.
For slides from Bible study about a mustard seed: How Big Is Your Faith?