I'm in the same boat: my standards for myself are way lower than when I work for other people.

I think self-discipline doesn't cut it. What you need is commitment devices: put yourself in a situation where it's harder/more costly to not do the work rather than do it. Have the environment do the motivation work for you, "tie yourself to the mast"

For example: time tracking, deadline for a public speech, deadline for a demo day, going to a dedicated room where only work is allowed, working with other people (even if they don't work on the same stuff as you), developing a good routine/habits. Keeping a log of progress/failures is good too.

It's hard stuff