I personally struggle with this and have found that forward planning really helps. For example if I want to write a report tomorrow and know that I am prone to playing video games instead, then I’ll unplug my games console and tidy away my games the day before and space permitting, I’ll write my report in a different room.
The less accessible you can make your go to distractions, the more likely you are to opt to do the thing you’ve been putting off.
Fabulous also has a really good guided meditation about acknowledging your impulsive and your more rational thoughts and consciously choosing which one to listen to. This, critically, makes you aware of your own responsibility in the decision making process and, for me at least, is often enough to highlight the flaw in the impulsive thought e.g. I know if I watch that 1 YouTube video then it’ll lead to 2 and before I know it I’ll not have done any work on my report and will feel really guilty about it so maybe I should just start that report instead and watch that video at lunch if I’m still thinking about it then.