The Basics
First you need to think about:
Once you have clarified that you can then start to think of the foundations.
The four simple foundations to guide behavioural change initiatives:

Heart (emotions)
Those in marketing and advertising know it. Hollywood knows it. Politicians know it. If you get the emotions you get a lot.
This means that when engaging in behavioural change initiatives you will absolutely need to think of how to stimulate emotions (the right ones!).

Body (action)
Once you do something it becomes much easier to do and you remove many blocks to doing things. In addition doing things can in itself be rewarding.
Note that many succesful movements and initiatives involve certain actions and rituals.
When you are involved in a behavioural change initiative you need to think clearly of how you get to action as quickly and easily as possible.

Brain (logic)
We can and do think rationally – to a degree!
Therefore we need to also tap into rationale and logic and provide good reasoning for change initiatives. However, this may be coloured by emotions.
Nevertheless, any change initiative will also need to have solid logical rationale to it to engage the brain and give it direction.

Peers (friends)
We know that some of the most influential people are those closest to you which are your peers and particularly friends.
We humans have a natural tendency to conform to and accomodate social structures and influence and be influenced by those around us.
So when engaging in behavioural change initiatives you will need to think of how to activate, use, and engage peer networks.
Complemented by:

Simplicity (ease)
The concept of “cognitive ease” is underestimated in many change initiatives.
The easier it is to change, or make the first step, the higher the chances of change. The more complex, the lower the chances.
So give a lot of thought as to how to make the process as simple and as easy as possible.

Environment
The environment you are in exerts a constant influence on your daily behaviours. This includes social aspects such as local or corporate culture, but also physical aspects such as office space, available resources, and much more.
When engaging in behavioural change initiatives think carefully about the general or specific environments people are in.

Structures
Structures help to give clarity and clearly guide people along a change process.
The more structure and clarity we have the easier it becomes.

Resources
The most common resource we think about in business is that of money. This is correct.
But the most important in change processes may be time and cognitive resources. Change processes take up extra brain processing time, but also involve investing time.
If you don’t have the resources, or people can’t or won’t invest the resources, change will be a challenge.