Long-time Dallas Seminary professor Howard Hendricks said that every follower of Christ needs a Paul, a Barnabas and a Timothy.
What Hendricks is saying: everyone needs (a) to build into be built into/mentored/discipled by someone (b) to develop relationships of mutual benefit and encouragement with other friends and (c) to build into/mentor/disciple others.
Who is your Paul? Who is your Barnabas? Who is your Timothy?