Now as to staying on topic here goes...
Now if I may continue my opinion Ash as to what I was trying to convey which is based on the Word of God/the bible.
The statements made by Jesus in John 6:53-58 precludes a direct reference to the Lord's Supper and He is not teaching here that recieving that sacrament is the one requirement for eternal life or that it is the thing through which His saving benefits are accepted.
Looking back at John 6:35,40,47,51 flesh and blood are pointing back to Christ as the one crucified and the only way to have life.
Jesus is talking more on faith here, the faith to accept Him as the one God sent as a sacrifice.
The Lord's Supper is similiar to what I had said previously about baptism in that an outward ritual does not neccessarily bring about any inward work.
However I'm not saying that it can't either, I'm trying to make a point here that baptism is not of any ritual requirement - at least not directly anyway.
Now as for washing/drinking John 4:13 Jesus here is talking about himself as being a fountain of Living water and since He is the Word made flesh He speaking of drinking in the Word, Himself, the Word of God.
How does one stay alive without water?
In the same way we who have been born again we as Christians need to stay alive in Christ through the drinking/reading, hearing of the word of God.
Just like a plant who needs water to grow and survive we to as Christians need to continue to drink in the Water of Life, Jesus Christ, the Word of God.
Now as for washing in the Word Jesus also said in John 7:37,38 that streams of living water flow from within the one who drinks of Him and by that it means that the Holy Spirit who would wash you in the Word.
When Moses and the Israelites passed through the sea it was a symbol of baptism. 1 Cor.10:1-4 speaks about this , "that they all ate the same spiritual food and drank the same spiritual drink", they drank from the spiritual rock and that Rock was God, the Word of God, Jesus Christ.
1 Cor.12:13 talks about that we as Christians are baptized by one Spirit into one body and that we are given the one Spirit to drink. We become regenerated by the Holy Spirit.
Why you may say - so that our lives would overflow/be washed by the fruit of the Spirit [Gal.5:22-23; and remember what Jesus said in John 7:37-39 about streams of living water flowing from within].
And now it is fitting that I should finish up here with this scripture from Rev.21:6 He said to me:"It is done. I am the Alfa and Omega, the Beginning and the End. To him who is thirsty I will give to drink without cost from the spring of the water of life."
[Re-edited the question below on Oct.5/06 to make the answer I gave below it more clear.]
How does one go about overcoming the world in ones self and eventually becoming mature and strong in Christ after being born again?
By being saturated in the washing of the Word of God by the Holy Spirit and us drinking in the written Word of God by reading/hearing and mediatating on it day and night.