Psalm 112  The man "who fears the Lord"  and " delights in His commandments" is called "blessed" or happy.   To fear or revere the Lord , "is the beginning of wisdom"  and " A good understanding have all those who do His commandments." ( Ps. 111:10)  To delight means to incline to, bend, or be pleased with, to desire.   So... to be "happy"  we must have a righteous, reverent, fear of Jehovah, the Most High God.. and a heartfelt desire to do what He has commanded. 

The psalmist then lists the many blessings that God desires to bestow on those who meet these two qualifications:

He will bless your children and grandchildren.
He will bless you financially.
He will give you light in the darkest of times.
He will make you like Himself in graciousness, compassion, and righteousness.
He will make you "well" - do good to you and for you.
He will be on your side in legal judgements.
He will keep you from being "shaken".
He will remember you forever.
You will not be afraid of bad news.
Your heart will be steadfast and trust the Lord.
You will overcome the enemy.
You will be generous to those in need.
You will have righteousness .
You will be lifted up in honor.

The Bible dictionary has this to say about fear;
"Religious fear is the human response to the presence of God."
When God Himself appears to us and we experience the reality of His holiness we will be overwhelmed with awe and fear and fall on our faces before Him.  "The God of Israel is an awe-producing God because of His majesty, His power, His works, His transcendence, and His holiness." 
We will learn the "fear of God" as we experience His Presence - as we see His works, His power, His salvation, His majesty.
The fear of God is transformed from terror into "respect and reverence in which trust" is prominent, by the covenant relationship we have with Him.  In the Old Testament this was the covenant of the Law, but for us it is the New Covenant through Jesus Christ.
Fear of the Lord will result in worship and obedience.
Fear of the Lord is required by the Lord... Deuteronomy 10:12-13 "... what does the Lord your God require from you, but to fear the Lord your God, to walk in all His ways, and love Him, and to serve the Lord your God with all your heart and with all your soul and to keep the Lord's commandments and His statutes... " 
We learn the fear of the Lord by reading His Word and doing it every day. ( Deut. 17:19)

If we have the right "fear of the Lord"  we will "delight in His commandments."  We will want to order our lives according to His word and trust Him in all things.  We will joyfully serve Him and give Him our whole hearts.  We will love Him with our whole beings.
And when we do this... we will be blessed. Truly happy.
Praise the Lord!

Father in heaven,  teach me the fear of the Lord.  May I experience the reality of Your holy Presence. May I gain understanding of Your Word and do all that You have commanded, by the power of Your Spirit in me. To the glory of Your Name and through the One in whose name I pray,  Christ my Redeemer ,my King, and my Lord.  Amen.