So, what does it mean to be responsible? I submit that it is simply to do what you say you will do, and fully "own" everything you do.
Do what you say you will do.
Keep your promises. Don't make promises you cannot keep. Don't make "half-promises" that are more like suggestions. If you're going to commit to something, then commit to it. This goes back to the whole idea of "let your yes be yes and your no, no." Do what you say you will do.
Fully "own" everything you do.
Before you begin something, know what it will entail (to the best of your ability). And once you've begun something, keep at it - don't leave things unfinished. Also, stay true to your work. Own up to any mistakes and take pride in what you do right. Don't be afraid to ask for help, often asking for help is the most responsible thing you can do.
And with that, I'm going to get onto a project I've committed to for a friend. He's my friend and I said I'd get it done.