Undefending pawns?

I've recently made the embarressing mistake of leaving my pawn hanging due to moving the knight that was defending it. The first time I made this error (e4,e5,nf3,nc6,bc4,nf3,d3,na5) I was honestly very tired and sleep deprived so I figured thats probably why I made that error and I'll try take note to never do it again (and honestly I wasn't sure how to prevent this happening again anyway) but then in my most recent live game on this website I made the same (very stupid on my part) mistake although this time I have no excuse which left me wondering how do I deal with this issue? Will it just fix itself overtime as I continue to progress in chess over time?

Not moving a piece twice in the opening would be a good place to start.

Thanks for good advice, I think I somewhat ignored the don't move a piece twice rule compared to the rest of the basic principles

It's almost always a bad idea to move a piece twice early. Unless my opponent leaves a pawn hanging I never do it. Another example would be is if I play a Sicilian and white plays some early Bc4 Qf3 garbage going for an early mate "threat" I might look to play e6 and a6 then move my knight twice to c6 then e5 and win the bishop pair early. But if my opponent is playing proper then I always follow opening principles. Develop all your pieces, connect your rooks and THEN look to attack.

JSB53 wrote:

Thanks for good advice, I think I somewhat ignored the don't move a piece twice rule compared to the rest of the basic principles

I'm just a duffer myself, but ultimately, you need to be aware at all times, simultaneously, the position and status of every one of your pieces. Lapses of awareness of any element of your position, be it material, tempo, space, king safety, will result it your game being played at less than your true potential.