I have found meaning in my life by becoming a Christian, reading the Bible, and praying. I found that the purpose of humans is to glorify God, and I find much meaning in serving Him.
Personally, I find the most meaning in my life through helping others. I spend a lot of time volunteering when I am able, and when I am doing things for others is the time when I feel most fulfilled myself.
I have found the most meaning in my life in my children and my church. Without God and my family I would be lost. Everyone has to search their own lives for what means the most to them, it is going to vary from person to person and can change for you as you age.