Recently, a colleague & a good friend of mine talked about the problems he is facing in his project, inter-team loss of credibility, poor communication, & the inability to keep the personal away from the professional. I did not really have too many words of advice for him at the time but since then, I've spent a little bit of my ghastly commute thinking on these issues. One of the problems of junior-mid level supervisors is the apparent lack of authority without any subsidizing of responsibility. Here are a few thoughts on how to handle the crisis of powerlessness.
The Project sponsor/boss: This is the person who actually has institutional power. You do not. But you need to be in his good books, prove that you're capable of handling your own team & that this frees his time up for other activities that need his attention. A good amount of confidence from your boss in you will surely influence what you mean to your team.
The power of knowledge: You're leading the team because you know more & have more experience. Make sure that this shows. Be careful so as not to discourage your team, & be extra careful not to slip into micro-managing problems that aren't supervisory. Establish your credentials & be available. Some managers detest any hands-on help, however; if you ask your team-members, they often look up to a manager who'll role up his sleeves & work with them.
The power of camaradrie: To whatever extent possible, be a friend to your team. If your team lunches together anyway, that's great. If not, do what you can to increase more social/personal interaction in your team. Remember that 'trust' is the intangible component of all delivery models. Throw a challenge to your team, & make sure you lose!
The power of humility: Often unexplored, but a manager/supervisor walking up to a team-member asking for help (& not demanding a task) is a great team-builder. This demonstrates the authority in a given matter of your team member over your own, & thus reduces his insecurity. In return, there'll be more acceptance of your say in the matters of the project.
General: If you need them to stay long hours on certain days, what will you do to make sure that they get the afternoon off when there isn't much happening? On a busy day, will you prepare the status report instead of your team member? Can you create responsibility-centers in your team so as to empower your team members? who are you growing to be you?