How can a Christian life touch others?

The Bible refers to this act that you speak of as “ministering” which in its basic definition is simply attending to the wants and needs of others. However, to minister to others one must first be willing to submit themselves to the Lord in all humility realizing that before they can hope to help others.

We see that humility is a prerequisite for man when serving or approaching the Lord:

Psalms 138:6Though the LORD be high, yet hath he respect unto the lowly: but the proud he knoweth afar off.
See All... Though the LORD be high, yet hath he respect unto the lowly: but the proud he knoweth afar off.

This was demonstrated first by our Lord in His earthly ministry as an example for us to follow:

Matthew 20:25-28 [25] But Jesus called them unto him, and said, Ye know that the princes of the Gentiles exercise dominion over them, and they that are great exercise authority upon them. [26] But it shall not be so among you: but whosoever will be great among you, let him be your minister; [27] And whosoever will be chief among you, let him be your servant: [28] Even as the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.
See All... But Jesus called them unto him, and said, Ye know that the princes of the Gentiles exercise dominion over them, and they that are great exercise authority upon them. But it shall not be so among you: but whosoever will be great among you, let him be your minister; And whosoever will be chief among you, let him be your servant: Even as the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many.

Which Paul himself also practiced:

Acts 20:19Serving the LORD with all humility of mind, and with many tears, and temptations, which befell me by the lying in wait of the Jews:
See All... Serving the Lord with all humility of mind, and with many tears, and temptations, which befell me by the lying in wait of the Jews:   

Which he also commended other believers for their humility and willingness to minister to each other:

2 Corinthians 8:1-5 [1] Moreover, brethren, we do you to wit of the grace of God bestowed on the churches of Macedonia; [2] How that in a great trial of affliction the abundance of their joy and their deep poverty abounded unto the riches of their liberality. [3] For to their power, I bear record, yea, and beyond their power they were willing of themselves; [4] Praying us with much intreaty that we would receive the gift, and take upon us the fellowship of the ministering to the saints. [5] And this they did, not as we hoped, but first gave their own selves to the Lord, and unto us by the will of God.
See All... Moreover, brethren, we do you to wit of the grace of God bestowed on the churches of Macedonia; How that in a great trial of affliction the abundance of their joy and their deep poverty abounded unto the riches of their liberality. For to their power, I bear record, yea, and beyond their power they were willing of themselves; Praying us with much intreaty that we would receive the gift, and take upon us the fellowship of the ministering to the saints. In addition, this they did, not as we hoped, but first gave their own selves to the Lord, and unto us by the will of God.