The only preparation is to be worthy of taking it.
1Co 11:23 For I have received of the Lord that which also I delivered unto you, That the Lord Jesus the same night in which he was betrayed took bread:
1Co 11:24 And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me.
1Co 11:25 After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me.
1Co 11:26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come.
1Co 11:27 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord.
1Co 11:28 But let a man examine himself, and so let him eat of that bread, and drink of that cup.
1Co 11:29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body.
1Co 11:30 For this cause many are weak and sickly among you, and many sleep.
1Co 11:31 For if we would judge ourselves, we should not be judged.
Paul gives directions regarding the Lord’s Supper in the 1Corinthians 11:23-30. Some have misunderstood verse 26, which says: "As often as ye eat this bread and drink this cup," and interpret it to say "take it as often as you please" But it does not say that!
It says "as often" as we observe it, "ye do show the LORD’S DEATH till He come." And Jesus commanded, "this do ye, as oft as ye drink it, in remembrance of me." (Verse 25.) We do it in remembrance of THE LORD’S DEATH - a memorial of His death.
Jesus instituted this New Testament ordinance ON THE EVE OF HIS DEATH. It was the 14th Abib, Hebrew calendar. He was our Passover, sacrificed for us and He was sacrificed on the same exact day of the year that the Passover lambs always had been slain. As the Old Testament Passover commemorated Israel’s deliverance from Egypt so the New Testament Lord’s Supper is a continuation of the Passover with different emblems that commemorates Jesus' death, and our deliverance from sin. Immediately after the last Supper, Jesus and His disciples went out to Gethsemane where later that night Judas Iscariot led the bloodthirsty mob who seized Jesus, and led him away to be crucified during the daylight part of the same 14th day of the month.