Possible Clues:

• Elected, bring to bear concealed power with little skill
• Like beginner, one immediately succeeding, capturing pawn with queen
• Raw x per this
• At home, putting power into exercise is unprofessional
• Amateurish batting performance at first: strive to rein it in
• One succeeding when boxing each amateur
• One succeeding around theatre, flipping amateur!
• Windows once seen in entire building? That's amateur
• Bungling agent held up by one immediately following
• Get in old forward, appearing as amateurish