Behavior Design in Practice means knowing how and when to add techniques...
The techniques/tactics are not the starting point of your solution, they are planned once you know what needs to change (by doing a behavioral analysis), what actions we are looking to enable, for whom, and in what context.
Once you know all this, then using behavior change techniques will open up a whole new area of possibilities to design with less risk and better outcomes. (you can incorporate many techniques in a solution or feature)
Remember, as a designer, change-maker, or innovator, one of your aims is to help your customers, employees, or even yourself make better decisions, meet needs and create delight in an experience.
My advice: >Follow the principles >Use the evidence >Work systemically >Look at both the individual and the system >Be contextual >Test >Iterate >Evaluate >Above all, strive to help others