I first met David Housego at university, while we were training to be officers in the Army Reserve. Often, in the mornings as we formed up for parade, he'd wait until I appeared so he could stand next to me. I assumed it was because he admired me and so, when we graduated, I thanked him for being there for me. He looked at me as if I was completely mad.

"Mate," he said, "I knew that as long as the inspecting officer saw you first it wouldn't matter how bad my uniform was ... I'd be just fine." He was that sort of bloke.

For years we were close. We kept each other sane as we slowly learned to navigate our way through life. Like everyone else, we found our paths peppered with organisations that were fundamentally dysfunctional; salted with individuals who didn't seem bothered making an effort to understand others.

David, however, always seemed to understand what life should be about, even if this did seem to involve listening to a great deal of live music. So what did he teach me about the meaning of life? As I write I feel him again staring; looking at me as if the answer should be obvious. To him it always was.

"Live", he'd say. "Don't waste time just sitting back waiting for something to happen - engage." There was always a choice for David; to act or do nothing. When the way ahead was blocked he simply found a way around it.

In our short military careers I'd acted slowly and correctly and received an attachment to a British cavalry regiment. David acted faster, moving inside the decision loop of the bureaucracy. He'd found himself in London without the appropriate accreditation for a posting, something that would have stopped me; it was a mere trifle for him. Looking around, he saw he could join the territorial SAS, so he did so. He passed selection; sailed through training; then broke his ankle on his final parachute jump before receiving his wings. He was disappointed but for him the point was never about the badge - he was living, involved, and pushing himself. And that's his second message.

David could learn, plan and prepare, skills that aren't as ordinary as they should be. At other times our ability to actually influence what's happening seems marginal. This doesn't mean we're impotent. Change will come: it always does. What's important is being prepared for it and pushing the levers in the right direction. You never know how life will unfold or which particular opportunity will reveal itself. The point is to be ready for that moment.

There are distinct aspects to learning: the technical, the theoretical, and the transformative. We all need to master the technical stuff, whether it's basic addition, complex accounting, or how to strip and assemble a machine-gun. David got these because he could see their purpose. Above this level sits doctrine, theory, or the "right" way to do things. David would accept this and comply, although he always hated being trapped in a web of procedure, routine, and rigidity. His ability was to push further and question procedure until he'd make a breakthrough or found some new, better way of accomplishing things. The moral is keep pushing.

Once he'd found his solution David learnt to lead. Selling your idea to others can be hard, particularly if you're not in a job where people have to listen - a situation everyone in the public service experiences on a daily basis. That's why many learn instead just to keep their heads down and focus on their arc of responsibility.

David, however, always seemed to know where he was going. What was perhaps more surprising was that he was normally prepared to listen to advice along the way. This didn't mean he'd always take it, of course, and I still believe this is why we came in second during that night map-reading exercise. Leading doesn't exclude listening and accepting this particular bit of well meant advice might have been a good idea; not that I haven't long put that particular incident behind me. But if you don't want to risk standing paralysed and being by-passed by others, you need to take the occasional, sensible risk and step into the dark. David was never afraid to leap when it was necessary.

However I've left for last the biggest lesson David taught me, the insight that gave him the leverage to achieve everything else.

Love. Not everyone will manage to find their Christine, of course, but for my mate this partnership was to became the rock on which everything else rested.

We all come to terms with our mortality in different ways. It's trite to say money, or power, or winning doesn't matter: they do, and there are a lot of people in Australia at the moment who are tasting the bitter ashes of political defeat in their mouths. The point is, though, to pick yourself up and move forward; never to allow yourself to be defined by what you can't control. Decide what you need to do, determine what's right, know that with certainty deep inside; then work toward accomplishing it.

Live. Life is too precious not to.