It is all very well telling us ways how not to seek spiritual fulness, as Paul does in Colossians 2. But how do we do it? How do you get it? This is where he goes in chapter 3. Here is the main thrust:

Set your hearts on things above - your affections, desires, delights
Set your minds on things above - your plans, what you want to achieve, your life-goals and thought-life and dreams

The Apostle is deeply practical in answering the how and why questions.

Question: Why set our hearts and minds on things above and not on earthly things?

Answers:

Because you have been raised with Christ. We have been given new life from the dead with a resurrected King who is seated in majesty and power (3:1)
Because we died to this world in order to made alive to God in Jesus Christ. And we have confidence that when he returns in glory, we will be with him (3:3)

Do you know him? Are you delighted with him? Are you in awe of him? Do you find him beautiful and compelling? Do you love to call him master, boss, Lord, champion every day? Do you hail his victory, like people hail victorious Olympic athletes only more? Do you make him your role model? (so good to hear Olympic atheletes doing so this week!). Do you want to do what he is doing, follow where he is leading this week? These things encapsulate the "why" of setting your heart and mind on things above. Christians are new creatures. We - literally - died to our old self. We have been - literally - made new.

Question: how do we set our hearts and minds on things above?

Answers:

Not by the human methods of chapter 2 - religious observance, superspiritual vain imagining and aesthetic self-denial, as if those will do us any spiritual good. They don't. They are of this world and therefore have no spiritual power
First by reckoning on this new identity. We are not trying to achieve this, trying to remake ourselves. We have already been born again. Now we are living in the light of it, living as the people we have been recreated to be. Say to yourself today "I have been raised with Christ. I died and my life is hidden with Christ in God." (Get hold of the great older New Frontiers song on this verse, David Fellingham I think, and sing it!)
Then we start to identify and put off - put to death - things that belonged to our old nature but not to our new one. Thats v5-10. Don't be sexually immoral, don't commit idolatry in any of its various forms, don't be greedy. We used to be like this, now it just doesn't fit with us. Note this is NOT aesthetic moralism - don't do these things to deny yourself pleasure. This is new nature stuff - don't do these things because they will destroy your pleasure in being who you really are
Then we start to identify and put on the things that go with our new nature. That's verses 12-13. It reads almost like a practical how-to list of growing in the Galatians 5 fruit of the Spirit. We really can decide to grow in enjoying and living out godliness
Let the following overall umbrella characteristics obsess you (v14-17):

- love
- the peace of Christ exhibited towards each other in the body
- thankfulness
- the word of Christ, which needs to richly dwell among us as we teach and admonish each other and as we worship with gratitude
- submission of everything we do to God in the name of the Lord Jesus