I have always been taught to “think before you act” – I should  consider what exactly I want to do; why; and what the impact is. This way, you have clarity on what you’re doing, and you can avoid making the wrong decision or upsetting people (especially important in leadership).
However, we’re working in business around the globe, using real-time communication, and keeping up with continuous improvements technology; and we need to keep pace with a constantly changing environment – and this means changing our decision making process to match this faster pace.
The “OODA Loop” is not new – it was developed by US Air Force Colonel John Boyd in the 1950’s, and refers to the recurring decision cycle of: observe-orient-decide-act. The quicker this cycle can be processed, the more an organization or individual can gain the upper hand, by being one step ahead of their “opponent’s” decision making.
The model demonstrates a four-point decision loop that supports fast, effective and proactive decision-making:

You cycle through the loop by observing the results of your actions, reviewing and revising your initial decision, and moving to your next action. It needs to be a smooth, continual process, and the faster you can move through each stage the better. In fact, if you were to sit down and map out each step, it would slow down instead of speed up.

The initial concept was based on military combat operations. Consider a fighter pilot trying to shoot down an enemy aircraft. Before the enemy is even in vision, the pilot considers information of the enemy pilot (level of training, cultural traditions, etc). When the enemy aircraft comes into the radar, our pilot gets more information on speed and size of the enemy plane. A decision is made based on the available information. Our pilot can then loop back to observation: is the attacker reacting to the action of our pilot? Then to orient: is the enemy reacting characteristically? Is his plane exhibiting better-than-expected performance? Based on these, he can cycle back through the loop to making a decision on his next course of action, and carry it out.

If you’re looking to work on your leadership, and become a better leader, your first step might be to create an action plan. “In order to be a better leader, I want to do this, this, and this”. Whilst this action plan might focus your efforts, and provide a roadmap; it is just that: a plan.
When it comes to leadership, the way to produce the change of mindset – to improve the skills you require to become a better leader – is to act differently, rather than just think about it.
In fact, acting differently is more likely to make you think differently.
Someone once told me that, if I act like someone that I would like to meet, in time, I’d become a person that other people want to meet (and this is now written on a piece of A4 paper, stuck on the ceiling above my bed, and I read it every morning when I wake up). This is Boyd’s OODA Loop theory applied to being a ‘nicer’ person; but the same can apply to leadership. Act like the leader that you would like to have leading you, and in time, you’ll become the kind of leader that others want leading them.
You can try something new and, after action, observe the results – how it feels to us, how others around us react – and only later reflect on what our experience taught us.
In other words, we “act like a leader” and then “think like a leader”.