'Joy' is a deep feeling of happiness or contentment or gladness. 'Joy' is like a spring of water that keeps bubbling within the heart of the redeemed. 'To be full' means to be complete, satisfied, saturated, abundant, adequate or plentiful. 'That your joy may be full' could mean that your gladness or happiness may be at maximum.
In psalm 16:11, the Bible says; “You have made known to me the path of life, you will fill me with joy in your presence”. This is also repeated in Acts 2:28 for emphasis. "In the presence of God, there is fullness of joy, therefore you have to be in His presence for your joy to be full". When you follow the path as directed by God your joy will necessarily be full.
When you are in the presence of God, what do you do? You praise and worship Him. Since joy comes from Him, you will surely have it. Psalm 34:3 says; “Glorify the Lord with me, let us exalt his name together”. When you glorify and magnify Him, you will be radiant and joyful.
Apart from praising and worshiping Him, you have to be in a place where you can hear the word and share it with fellow believers. Hearing the word and meditating upon it will surely give you joy. Jer 15:16 says; “when your words came, I ate them, they were my joy and my heart’s delight for I bear your name”. Definitely the word of God will fill you with joy when you digest and meditate upon it.
A great hindrance to deriving maximum joy from being in the presence of the Lord is sin. Repentance will surely set you free from sins and you will be at peace with yourself and God. Being set free from bondage of sin will also give you joy. Even the angels of God rejoice when you repent. That is, there is joy in heaven concerning you when you repent.
There is indeed fullness of joy for those who are wise and are prepared for the Lord’s coming. Wisdom is crucial, and you must seek it. The five virgin out of ten that were wise had their joy full. They were well prepared for the Bridegroom. For your joy to be full, you have to be wise. To be wise in this context is to be well prepared or His second coming so that you can be joyful and end gloriously.
Seeking the face of the Lord through prayer can connect you to the Lord and thus make Him to remember you. Surely you will be joyful because there will be divine visitation and blessings will also accompany it.
In 1st Sam. 1:10, when God remembered Hannah, her situation changed completely for better and she became joyful. Seek Him through prayers always for sustainable fullness of joy. Hannah sought God through prayers and God visited her and she became joyful.
Focusing on spiritual matters like salvation of souls and witnessing for Christ will lead to joy. As you focus on spiritual matters, heaven will focus on your physical and spiritual needs and make sure they are met. If your needs are met, you will be happy and since happiness is embedded in joy, the joy will continue to be full and overflow.
Paul concerned himself with spiritual assignment and he finished his earthly race very well as recorded in 2nd Tim 4:7. He had a glorious and joyful end.
In conclusion, for your joy to be full you have to:
1. be born again. John 3:7
2. be filled with the Holy Spirit. Luke 15:7
3. focus on spiritual matters. 2nd Tim 1:14
4. equip yourself with the word and live it. Jer 15:16
5. connect to the Lord through ceaseless prayers. 1st Thes 5:17
6. be totally obedient and fear HIM. Ecc 12:13
7. be redeemed. Isa.51:11
Father in heaven, I want my joy to be full. Whatever I need to do to make it full, grant me the grace to do so. In Jesus’ name I pray (Amen)