Availability does not mean inserting ourselves into places we are not called. It means to open our lives to the unique calling God has for us. The key is not trying to be someone other than God called and created us to be.
Availability therefore is a process of removing the barriers that would keep us from growing into who we are meant to be. Many of those barriers are connected to our ego and the false self. Pride and fear are perhaps the two greatest barriers.
A person ruled by pride is not receptive or open to change, they do not have a "beginners mind" and therefore they learn little. Life has a way of stripping our pride and at these times we become more aware of the Divine in our lives. Pride is the opposite of humility and is not a Christlike attitude (see Phil 2).
Fear keeps us from trusting that the gentle rule and reign of God is present in our lives. If we are ruled by fear then it is hard to trust that God is the shepherd of our souls. We fear the unknown because we do not trust Christ has already gone ahead of us. Christ's perfect love casts this fear out and opens us to losing our lives for his sake. We can trust the one who gave his life on the cross and whom God raised from the dead.