On your first question, good word choice can really help. Better verbs, adjectives, and so on can paint a much more vivid picture within the same character limit.
Similarly, as appropriate, using one powerful and memorable example could be better than trying to laundry list stuff.
In general, I think kids often think these sections have to be in a stiff, formal, “resume” style that ends up very bland. I think this is a missed opportunity to really make yourself stand out with strong, vivid, memorable descriptions.