Keep a list of the errors that you make frequently. For example, if you are often told that you are putting apostrophes in the wrong place, list this error together with a brief description of proper apostrophe use. Consult your list of frequent errors when you are ready to edit your paper and look specifically for these problems.
Most word processing programs have features for locating grammar and spelling errors. However, even the best of these programs can miss many problems. Often, they mark passages as problematic even though they actually work very well in the essay. The programs can serve as useful starting points to identify possible problems, but think of these as suggestions for review rather than as requirements.
Grammar and spell checkers cannot substitute for your own careful reading as they are not aware of your intentions. A spell checker, for example, will not mark “their” as a misspelling because it doesn’t know that you actually meant “there.” If you are uncertain about a grammar or spelling issue, consult a Writing Guide, visit York’s Writing Centre, or ask your instructor for advice.