You should treat every scene as you do the whole piece – meaning that you should outline the scene you are about to do, examine it to see if you have three acts (a beginning, middle and end).  Sometimes you can eliminate the first or last act if the audience has been given enough information so that they can fill in the empty space.  Be sure that there is some kind of conflict and that the character and/or the plot is being fulfilled, meaning that the little red dot of your outline is addressed.  

If you are having trouble with the scene, my usual tactic is to write the most obvious scene I can create.  The process of writing it raises the obvious question of why this is a cliché and may lead to a way to find a new angle, a way of approaching the scene that will give it some vitality.  You will always run into the problem of exposition.  It usually bore the hell out of the audience.  First, make sure that this information is really needed.  If so try to find a way to distract the audience from the fact that you are unloaded straight plot data.  One way is to put some action in the scene, watch the first “Terminator” and see how Cameron masterfully does this.  

Comedy is also a good bit of camouflage.  Use a subplot from one of the minor character that you can intercut with the information, an argument between the characters is also a good gambit.  Keep the scenes short and sweet.  Every scene should be good enough to be used at a clip for the Oscars.  If not, try to cut it or make it better.  You might not achieve this goal every time but aim for it.