Abraham’s servant did not ask for some extraordinary sign, like fire to fall from heaven. What he asked for was to see some indication of one who would make a valuable wife in that culture—one who was friendly, hospitable and hardworking. The unusual circumstances, however, ultimately proved Rebekah was chosen by God to be Isaac’s wife.
Does this Biblical example teach a fail-proof method of knowing God’s will? No. God promises us his guidance and his presence, not necessarily external signs. He may choose to grant us events that, upon looking back, we can trace to his leading. But that should not be expected. Much of God’s will is learned in the struggle of doubt and faith.
He wants us to live by the principles he’s laid down in the Bible. He is concerned about how we live as much as what we do. That doesn’t mean that what we do isn’t important, for our actions reflect our allegiance to God. But doing God’s will means living one’s life in obedience to all that he has revealed to us.
God also gives us his Word and the godly advice of others to discern his will.