1 John 2:28-29 (KJV)
28 And now, little children, abide in him; that, when he shall appear, we may have confidence, and not be ashamed before him at his coming.
29 If ye know that he is righteous, ye know that every one that doeth righteousness is born of him.

In verse 29 doeth refers to practices (as translated in the NKJV). We can choose to practice what is good and right according to GOD or practice what is bad and evil according to GOD.

The more we practice something the better we get at it. So if we practice sin we get better at it the same goes with practicing in doing what is right.
When we practice righteousness we demonstrate that we are born again by the Spirit of GOD but if we practice evil we show that we are not of GOD and do not want to come to Jesus Christ.
“John 3:20-21 (NKJV) For everyone practicing evil hates the light and does not come to the light, lest his deeds should be exposed. [21] But he who does the truth comes to the light, that his deeds may be clearly seen, that they have been done in God.””

Therefore let us, who are in Jesus Christ – born again, be encouraged to decide to follow Jesus, obeying Him, practicing righteousness. The more we do the easier it gets and the more we demonstrate that we are born of GOD.

“Galatians 5:16-26 (KJV) This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh. [17] For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would. [18] But if ye be led of the Spirit, ye are not under the law. [19] Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, [20] Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, [21] Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God. [22] But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, [23] Meekness, temperance: against such there is no law. [24] And they that are Christ’s have crucified the flesh with the affections and lusts. [25] If we live in the Spirit, let us also walk in the Spirit. [26] Let us not be desirous of vain glory, provoking one another, envying one another.”