The seeds of fellowship...

 So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, complete my joy by being of the same mind, having the same love, being in full accord and of one mind. Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. Let each of you look not only to his own interests, but also to the interests of others. Have this mind among yourselves, which is yours in Christ Jesus, who, though he was in the form of God, did not count equality with God a thing to be grasped,
 (Philippians 2:1-6 ESV)
Fellowship, refered to here as "participation" is the sharing of life in Christ.  It does not "come naturally", but supernaturally.  In order for it to thrive we must all be submissive to the Spirit of God, recognize the significance of others, and seek to serve Christ and others above ourselves.  We must not grasp at our own greatness, but go for God's glory above all things.