The answers to the clues below will have something in common.

1. Stand proud
2. Be firm
3. Set to work vigorously
4. Work hard and steadily
5. Remain resolute and unemotional when faced with adversity 
6. Continue to participate in an activity or job, but to a lesser extent.
7. Remain focused on a goal and not be distracted by problems or setbacks
8. Pay attention to what's going on around you, listening for clues as to what's going to happen

Answers:

1. Hold your head up
2. Put your foot down
3. Put you shoulder to the wheel
4. Put you nose to the grindstone
5. Keep a stiff upper lip
6. Keep your hand in 
7. Keep your eye on the prize
8. Keep your ear to the ground - - - idiomatic expressions containg body parts 

Credit:
David W. Cromer (#1, 2, 6)