In reply to RJP:
Finger strength develops slowly. Be patient, nobody has strong enough fingers.
For now, I'd just try fingery problems at the bouldering wall. The problem with pushing your grade is that often I find myself moving inefficiently over holds/terrain etc which I find challenging. It's great for your climbing to discover a more efficient way of doing a hard move.
So yeah....keep trying those fingery problems and look for the most efficient way of doing them. If somebody who is quite good at the wall is cruising them, watch their technique carefully, even ask for advice/beta.
Remember to rest well, finger strength is only gained if you rest after a hard bouldering session.
If you keep trying hard, there is no way not to improve.