With actors who are really new to it, it can be an easy fall-back for a director to just explicitly tell/show them how you want it done. That's how it was for me, with my first couple shorts, and I don't think that's unusual, when the director and actors are equally inexperienced.
As samwagner mentioned, experienced actors would be insulted by that, and for good reason -- when you give them explicit instructions on exactly how you want it done, you are taking away their creativity. An actor acts, and they're doing their best when they surprise the director.
After having been able to work with some more experienced actors, I've still occasionally dipped into the talent-pool of untrained friends, and I've found that they respond rather well to the same type of communication that I give the more experienced actors. Untrained actors generally suck at memorizing lines, they don't know how to rehearse blocking, and they suck at continuity, but that doesn't mean they can't deliver a great performance.
If you just communicate with them about their character, the situation they're in, their motivations, and how they might react to the situation, I think you'll get an actual performance out of them, instead of a wooden re-enactment of the rigid instructions you might have otherwise given them. Ask questions, allow their to be a conversation, and guide the conversation in the direction you want it.
As little kids, we all knew how to play pretend. Though there's plenty of more advanced theory and technique, at it's core, that's all acting is. Actors are at their best when they're playing and having fun, and rigid readings from directors will take an actor out of their element.
And besides all of that, I think you should also consider your own development, as a director. If you start out the wrong way (giving explicit directions), you might make a habit of that, and then you'll eventually have to un-learn those bad habits (like I had to). I think the easier path to follow is to just start working on your communication skills, from the get-go, and that doesn't need to involve telling someone exactly how to do their job.