"As we have therefore opportunity, let us do good unto all men, especially unto them who are of the household of faith." (Galatians 6:10)
C. S. Lewis, in his book Mere Christianity, spoke of Christianity as a "Great Hall" with doors that lead to different denominations lining either side. He also said that we were "under orders" to pray for them. It can be a waste of time to try and evangelize a foreign mission field when the church structure at home is decaying and coming apart at the seams.
I'm speaking to Christians: Please. Let's unite and let God knit our hearts together. The inward sins of pride and hardness of heart, apathy and ingratitude—the ones that God sees—eclipse the outward sins that everyone else can see. And Jesus' shed blood forgives them all. We have no business shunning people who are struggling with an emotional dependence to a sinful substance (drugs, alcohol, pornography) when we ourselves are touting an emotional independence that is supposed to pass as (a cheap substitute of) maturity and wisdom. Oswald Chambers says that "discernment is never given for criticism but for intercession." Focus on your brother and sister in Jesus and pray for them. Lift them up to God and forget about your needs. God will see to it that you're taken care of.
And the world will sit up and take notice that we have been with Jesus.
"Through wisdom is an house builded; and by understanding it is established: And by knowledge shall the chambers be filled with all precious and pleasant riches." (Proverbs 23:3-4)
We start in the basement, so to speak.
Then, when we believe on Jesus, God resurrects us from our interment and we find ourselves on the lowest floor of His house. This isn't a bad thing. Look around. What interests you? Check the library, the Holy Spirit is your teacher (see John 14:26; I've read of libraries in Heaven). You hungry? Jesus is "that bread of life" (John 6:48; see also vv. 54-56). Do the work of God where you are (see John 4:34). Or you can just sit with Him in the den (Psalms 46:10). As you explore the lowest floor, in humility, Jesus is going to say "Friend, go up higher" (Luke 14:10).
You may meet people on your way who are unqualified to be where (they think) they are. Remember: "Discernment is never given for criticism but for intercession". Don't let 'em get to you, pray for them and forgive them. Move on. Don't turn to the right hand or to the left (see Isaiah 30:21). Keep going. God will "exalt you in due time" (1 Peter 5:5-7).
At some point in your sojourn, part of you should be on the roof, watching and waiting. I'll explain: Jesus is coming. He could have come (I believe) a long time ago had we made ourselves ready (see Revelation 17:9). David compared himself to a sparrow watching (Psalms 102:7). Sparrows are diminutive and humble birds. I was told that in America they're an "invasive species". I guess you could say the same for Christians. We are not of this world. And eventually we'll fly away home… (See also Luke 17:31)