Use a linter to run through your code and identify style issues.
Edit your code to improve the style compatibility, based on the feedback from your linter. If you work with Python, consider applying autopep8 to automatically fix linting issues.
For the R users: a course participant found styler, which may do the same for R!
If you find code that is hard to read, or variable names that need adjusting, make a note to work on it. (Again, use #TODO or another consistent label!)