Sheila... one thing remains constant in the OT and the NT... and that is FAITH.
Hebrews 11:6 "But without faith it is impossible to please him; for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him."
How did the prayers of the OT get heard.... the main ingredient was FAITH! It takes that same FAITH today to have our prayers heard. Nothing has changed in that sense from the OT to the NT.
Read
Hebrews 11 to see this being addressed.