What skills and abilities any proofreader must have?

In my opinion good proofreaders are rate to find because they must have special qualities to intruduce good proofreading such : - a high level of skill in written English, including spelling, grammar and punctuation. -very motivative to work on their own, and to meet deadlines set for their work. Proofreaders are require to stay focused . Which may be long . Profreading requires a person who takes care of all details .well orginzed . -knowledge of IT ( computer knowledge ) -must have indurance .patience .

Good eyes, and good grammar 

A proofreader  should be very good at spellings and grammer and should possess great attention to details. 

It is widely recognized in its specialization

THanks for invitation,

Agree with the answer of Mr. Ali Mandour.

Writing Skills List and Examples

Research

• Analysis
• Reporting
• Report Writing
• Online Searches
• Identifying Audience
• Content Review
• Content Management

Interpersonal Skills

• Communication
• Empathy

Editorial Skills

• Copy Editing
• Copy writing
• Digital Media
• Drafting
• Editing
• Establishing Tone
• Formatting
• Grammar
• Identifying Theme
• Establishing Purpose
• Journalist Ethics
• Language
• Media
• Microsoft Office
• Proofreading
• Revising
• Spelling
• Structure
• Style
• Punctuation
• Strong Vocabulary
• Using the Rhetorical Triangle
• Devise Structure
• Establish Tone

Media Writing

• Newsletters
• Business Storytelling
• Blog Writing
• Journalism
• News Writing
• Organizing
• Print Writing
• Proposal Writing
• Social Media
• Web Writing
• Presentation Writing
• Creative Writing
• Feature Writing
• Magazine Writing

Technical Skills

• Outlining
• Pagination
• Production
• Distribution
• Layout Creation

Editing Skills ListPersonal Attributes

• Accuracy

• Budgeting

• Consistency

• Creativity

• Detail Oriented

• Flexible

• Interpersonal Skills

• Team Player

• Patience

• Negotiation

• Organization

Interpersonal Skills

• Collaboration
• Communications
• Coordinating
• Project Management
• Teamwork
• Author Meetings
• Consulting
• Contracts
• Project Coordination
• Verbal Communications
• Written Communications
• Working with Reviewers

Editorial Skills

• Copy Editing

• Clarification
• Developmental Editing
• Digital Content Editing
• Eliminating Jargon
• Fact Checking
• Grammar
• Incorporating Additional Input
• Indexing
• Language 
• Line-by-line Editing
• Manuscript Creation
• Mechanics of Style
• Punctuation
• Project Editing
• Proofreading
• Research
• Rewriting
• Rough Manuscript Edits
• Spelling
• Story Development
• Structural Editing
• Style
• Style Manuals
• Stylistic Editing
• Substantive Editing
• Terminology
• Tone
• Vandyke Checking
• Vocabulary
• Voice
• Web Publishing

Design Skills

• Design Supervision
• Final Manuscript Production
• Mark-Ups
• Mock-Ups
• Marking Color Breaks
• Marking Head Levels

• Typesetting
• Working Sketches

Computer Skills

• HTML
• Content Management Systems (CMS)
• Microsoft Office
• Online Editing
• Software
• WordPress
• InDesign
• Word Processing

Journalism Skills

• Applying Inductive Reasoning in Generating Storylines
• Applying Specialized Knowledge in Business, Health, Economics, Politics etc. to Stories
• Asking Tough Questions
• Convincing Editors to Let You Pursue Stories
• Coping with Deadline Pressure
• Creating an Effective Social Media Presence to Promote Articles
• Distinguishing Fact from Opinion
• Establishing Rapport with Others Quickly
• Evaluating the Legitimacy of Research Studies
• Extracting Information from Primary Sources

• Gauging What will Interest Readers
• Grammatically Correct Writing
• Handling Criticism from Editors and Readers
• Incorporating the Right Data to Support Storylines
• Interviewing Experts
• Networking to Identify Sources
• Overcoming Objections from Reluctant Sources

• Protecting the Confidentiality of Sources
• Questioning Witnesses
• Reading Comprehension
• Reconfirming Facts
• Researching Background Information for Stories
• Tapping Social Media To Identify Experts 
• Utilizing Deductive Reasoning to Guide Research for Stories
• Verbal Communication
• Writing with a Who, What, Where and When Focus

I think he needs to have a high level of skill in written English, including spelling, grammar, and punctuation.

•  Also the motivation to work on their own, and to meet deadlines.
• an ability to stay focused throughout an entire document, which may be long and technical