I skim through the latest edit(s) attentively by checking all the revisions of the user. If there were one or more bad edits from the user, I rollback them all. Moreover, if I made a mistake and want to revert it, I press undo and not rollback. Note that while rollbacking, you revert all of the consecutive edits one made without a reason and the rollback will not appear on WikiActivity, while regular undoing would revert one edit at once, give you a reason input field and it will appear on WikiActivity.
If you wanna know more about reverting, read this page: https://c.wikia.com/Help:Reverting