Sometimes, it isn't so much about adding resources as it is about making sure that the ones you have are assigned to the right tasks. Some resources may be more knowledgeable or efficient at certain tasks. A software architect who is working closely with the team may be able to provide valuable input to project management to reallocate resources.
If you see resources who are not working on critical items, you can suggest that they be reassigned to more important tasks. If a project is behind schedule, everyone needs to be working on the critical path to complete the most important tasks first.
If there are tasks being worked on in a serial manner, which may cause a delay, think about how the tasks could potentially be reassigned so that they can be worked on in a more parallel fashion.