You're right; even the most dedicated men and women in the Bible had their faults and weren't perfect. As the Bible says, "There is no one righteous, not even one" (Romans 3:10). Those words were true of them, just as they are true of us.
Only one man was perfect -- and that was Jesus Christ. This wasn't because He tried harder than anyone else, or because He withdrew into the wilderness so no one could tempt Him. No, Jesus Christ was perfect for one reason: He was God in human flesh. And just as God is pure and without sin, so Jesus Christ was pure and without sin. As the Bible says, Jesus "has been tempted in every way, just as we are -- yet he did not sin" (Hebrews 4:15).
At the same time, learn from the men and women you meet in the Bible. They often lived in difficult times, and their faith and love of God should be an example and encouragement to us. Learn from their failures also. The Bible says, "These things happened to them as examples and were written down as warnings for us" (1 Corinthians 10:11).
But most of all, make it your goal to live for Christ and be His follower. Begin your journey today by turning to Christ and confessing your sins to Him, and then by faith asking Him to come into your life and make you His child forever. Your life will never be the same.