Tips for Making Excuses & Responsibilities Please

Hi there,

I have a tendency to make excuses when in an argument, or say something that isn't true or wholly true to look better.
e.g. "Why did you do ...?" "Because W X Y" (When really it's Z, which is a selfish weak reason.) I also words things passively to escape responsibility, so something like "There kettle didn't boil..." instead reality "I forgot to press the button".

Can any one offer actual action items for how to combat this type of behaviour? I see a lot of articles saying to take responsibility for what you say, but how do you actually do that? How can you actually learn to stop yourself in the moment and say "No, this isn't true" or "this isn't what I mean to say".
How do I stop bulls&%'ing? I feel like I am attacked a lot, so I guess I try to defend myself.

Thank you.