So I really can be useful?

According to II Peter 1:5-8, the "trick" to being useful or fruitful lies with some pretty remarkable character traits. I'm thinking that by myself I would have no way to achieve all -- or any -- of these qualities (faithfulness, goodness, knowledge, self-control, endurance, godliness, brotherly affection, and love). But God, through His unending love, desires for us to have these characteristics and wants to give them to us if we seek them.

If you possess these qualities in increasing measure, they will keep you from being ineffective [useful] and unproductive [fruitful] in your knowledge of our Lord Jesus Christ.

But [by the way] whoever does not have them...  is nearsighted and blind, forgetting that they have been cleansed from their past sins.  II Peter 1:8-9 [emphasis mine] 

We would be useful to whom?
I think we will not only be useful to the Lord (which is, of course, our ultimate goal) but also to our friends, family, and co-workers. Think about it. If I am faithful at work, show goodness to my co-workers, exhibit self-control in my dealings with staff, management, and clients, am patient in my dealings with everybody, and express brotherly affection and love to everyone, then I’m going to be useful and fruitful in my job. I would agree, though, that my true goal in life is to be useful in God’s eyes above all others.

What does it mean to be fruitful or productive? Faithfulness, goodness, patience, godliness, self-control, and love have all been covered in this passage. Do they remind you of another verse in the New Testament? 

For the fruit of the Spirit is love,
joy,
peace,
patience,
kindness,
goodness,
faithfulness,
gentleness,
and self-control.
Against such things there is no law. Galatians 5:22-23

It is by the indwelling of the Holy Spirit that we take on His characteristics in our lives. We must let him control us. We must take an active part in embracing this fruit.

So there you have it. The "formula" for being useful lies in II Peter 1:5-8.
If we have these things and they are increasing in our lives,
then we will be useful and fruitful.

Now that is cool.