So, last Friday, I did make one minor mistake running the game clock at my game...I left the dreaded one second on the clock at the end of the first quarter

It did not have a significant outcome on the results of the game and neither coaches questioned it (It was a non-district game...a private school against v. a public school).
When I went down to the officials locker room to talk to the white hat, he told me I was doing a good job, but made the mistake of leaving one second up on the clock, which I acknowledged. He then gave me a tip...Have situational awareness.
I do need to develop this skill and start scanning the game clock, just wish I started doing this sooner rather than later.
My question to the above is...when do you usually scan the game clock, especially when the clock is running?
My second question is, after I got home from the game on Friday night, I looked over my notes (I started taking notes as to every single time the clock is stopped) and when I saw I had left one second on the clock, I was so angry at myself, despite the error not having a significant outcome on the game.
I realize that I was being hard on myself when I didn't have to be, since I am a new clock operator and am learning each time I go out.