Being a "boss" without the title is one of the most challenging jobs you will ever have. But doing it well will enhance your prospects for future promotions and a successful career in people management.
There has been some excellent advice posted above, and I would like to add to it. Where Pat9127 suggested speaking to your current supervisor for advice on this subject, I believe that managing (or supervising, or overseeing) staff is (or should be) very similar to providing service to customers. So, in that vein, I would ask the people whose work I am overseeing what is the best way to communicate work objectives with them. I have used this strategy successfully as a supervisor, manager, and director.
Face it, nobody wants a "boss." But everyone wants a Leader. Great leaders do not lead by force, but by consensus. Find common ground with each individual that you oversee, and then discover which method of communication works best with them.
Management is like customer service in many ways, and specific way is that "One Size Does NOT Fit All." A successful business does not treat all of its customers one way, and a successful manager does not treat all of his/her staff the same way. The "Golden Rule" may be to treat others the way you'd like to be treated, but the "Platinum Rule" is to treat others the way THEY wish to be treated.
Best of luck with this! I was in your shoes 20+ years ago, and the lessons I learned then are still relevant today.
The Angry Customer Strategisthttp://www.AngryCustomerStrategist.comhttp://www.Knowledgence.com