What have you learnt in the course of your career that would be really useful for colleagues here on the Learning and Skills Group to know about? It could be totally tactical ('Always begin a public presentation with a full set of lungs') or utterly strategic ("Never begin an L&D plan without first knowing which executive gives you complete support.")
The only thing it has to be is short.
To start off, here's my offering: Never say 'yes' to a training request without first asking 'why?'.
"Put yourself in their place / Understand your audience"
Of course you'll understand everything you're trying to deliver (no matter what the medium of delivery is) - however if it isn't clear, consise and easily comprehendable - the "learner" won't understand. And if you can "relate" to their scenarios/position - it's easier for them to understand and far more believable!
An essential question to ask following any learning intervention is "what are you doing differently / better as a result of the training?" After a while it becomes a habit to ask it. Even better, when people see you coming they know you're going to ask it....and after a while it becomes a habit that they think about the question even before you ask!