Worship is all that we are, reacting to all that God is, offering adoration in praise, prayer, song, giving, and living -- always based upon His revealed truth.
John 4:24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
The only access any person has to the Father is through the Son - 1 Tim. 2:5, so salvation is essential to spiritual worship.
The Holy Spirit must lead in worship – 1 Cor. 2:11, and we must yield to Him -- meditate on God's Word and talk to him in prayer.
Sin hinders the flow of spiritual things between God and man, Psa. 66:1, so it must be cleansed by humble confession to the Lord.
Private worship is essential to true public worship.