Let me say right up front this bit of advice is a tough one for the creative soul.
You’ll need to get a grip on doing this because you’re bound to make mistakes along this writerly life. And do we all struggle with this one!
We all make mistakes that require forgiving, and we are our worst enemies when it comes to forgiving ourselves. This can cripple a writer, effectively stopping the flow of words. It’s not always the big things, it seems to be the smaller accumulated things that grind creativity to dust. So however you find the way to do this, whatever method you use, learn or do it.
Clearing out the accumulated debris of life, of forgiving yourself, allows other things to enter your mind and many of these “other things” are great ideas.
Consider this as an emotional housekeeping and do it regularly; it seems our mistakes and regrets only pile up otherwise.
I note this is easier said than done (oh how I note this!) but it’s a skill to be practiced as assiduously as any other.
Forgive yourself. Everybody else has.
Update: I note keeping a regular writing journal works magic at this task. The physical act of putting pen to paper makes a concrete connection that creates cracks in the dam holding back all those regrets and should-have-beens.
Writing only for yourself, you can afford a level of honesty and candor that would be incredibly tough if the work was to be published.
I destroy mine after filling them.
As an extra note, I use a fountain pen. It’s a relic from my youth and I’ve finally figured out why I kept it all these years. There’s something quite magical about slowing down and… but that’s a topic for another day.