Concerts are never too short. Always charge for your concerts. It's a question of respect for the professionalism of the musician, and is a symbolic gesture by the audience that they are doing something worthwhile. Don't follow the examples of the people on the panel. The music world is very different today than it was 30 or more years ago.
Character is vital and involves perseverance, vision, ambition, and self-confidence.
The power of imagination is more important than your volume. Do not try to overpower the orchestra or overcome the acoustics of a hall. Do not press. Emphasize the note before a shift or big bow skip in strings. You must start from a place that is solid, not shaky, in order leap to the next note or string with confidence and accuracy.