I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service. And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God. Romans 12:1-2
What is the most important thing that God wants from you? The most important thing that God wants from you is to believe in His Son, the Lord Jesus Christ:
Believing in Christ unto Eternal Life
And
this is the will of Him who
sent Me, that everyone
who sees the Son and believes in Him may have everlasting life; and I will
raise him up at the last day. John 6:40
The second most important thing that God wants from you is to conform you to the image of His Son. He wants to make you like His Son, the Lord Jesus Christ. The second most important thing is your sanctification:
Your Sanctification
For
this is the will of God,
your sanctification... 1 Thess. 4:3
Also God wants you to be thankful and not forget all His benefits:
Being Thankful
In everything give thanks;
for this is the will of God in
Christ Jesus for you.
1 Thess. 5:18
God also wants you to be a good steward in your vocation; for you glorify God when you have a good testimony at your work:
Being Good Stewards in Your Vocation
Not with eyeservice, as men-pleasers, but as
bondservants of Christ,
doing the will of God from the
heart.
Eph. 6:6