For me I work mostly on my own, I have someone who proof reads my comic before publication (but honestly, I by that time I already feel too tired to edit what they point out so some grammars weren't fixed until after publication).
Before working on the final product though I would layout what the next 10 chapters are on the script, I usually edit them based on what have been slightly modified from previous chapters but always trying to keep the goal and lore consistent. You'd be surprised how changing a single dialogue can change the story a lot so I tend to avoid modifying dialogues too much.
Once I am satisfied I go through the script to double change dialogues, polish written scenes and settings and make sure things look good for illustration. Then I illustrate the pages. After illustrations I do the line work, flats and shading with a final touch of highlights. And then I do most of the process over again.
Because of this my work is very unsteady and I hope to one day find someone who can assist me so I can keep at my steady pace instead of feeling so exhausted all the time. I barely have any time to spend with my family and friends and it would be nice to still work on my hobbies and on my personal life.