Ooo, yes, I know that feel! That happens a lot with me also! I’m a pretty impatient person (a-and l-l-lazy…wwwwwww) so I have a gazillion WIPs that never get finished within a year ; - ;
Anyways, back to the point. One of the things I would make it a habit to not finishing entire pictures in one seating. Take a break in between to space out the time that you draw the picture. Sometimes, it can help you see some mistakes you missed! I found that in livestreams, when I try to finish a picture in a short amount of time, I rush through drawing the picture and often end up not satisfied ; - ;
Another thing I do is to have a pretty clear idea of how you want the final piece to look like, and often zooming out while you work to see how much you’ve come to creating that picture you are thinking in your head! Always try to look at your work and ask yourself, “What can I do to make this better?” When you see the spots that need work, go on and work on it. I leave major colour editing till the very end, but you can always try altering colour schemes/levels/contrast while you’re working! um.. don’t be afraid to start over on the piece if you feel like it’s not going anywhere. When you can boldly start that piece over, you’ll be able draw much faster, and perhaps with a better picture of how the piece should be!
That’s about all I can think of at this moment! Sorry this became longer thant it needed to be (and well, I really hope this is what you meant with your question hahaha)
O.<)b Good luck!