To know, love and serve God in this world in order to be happy with Him forever in heaven.
For everyone the reality of God’s will, what exactly it is we have to do in order to serve him, is different.
I tell my teenagers: Pray to know His will. The prayer will also lead to greater love, as does the reception of the sacraments. Knowing Him is accomplished through prayer, scripture reading, lives of the saints.
In the morning a little prayer just to do His will for* today*, is sometimes enough to help during a busy, crazy time in your life.
You might not know much until eternity, eh, but if you are faithful in all those little things you are doing it all right.