I also advise you to listen to as many plays and drama documentaries as possible. Make a note of who the directors / producers are and contact them with your carefully prepared voice reels. It will probably do no harm to praise a programme of theirs that you have heard, but don’t overdo this. Sara Davies of the BBC gives some excellent advice:
“I’m sure each department has slightly different needs, but in Bristol we find the most useful voice reel is one that includes straight narration, i.e. telling a story in the third person, preferably with a couple of bits of dialogue included, so we can tell how skilfully they can handle different voices in a story; a piece of monologue in something near to the actor’s natural voice and maybe one in character or with an accent; perhaps a dialogue with one other actor (but not a multi-character scene) and some poetry.”
I would add to this that you should never go on longer than absolutely necessary to show what you have to offer. Producers are extremely busy and tend to be impatient of repetition. 8 minutes for the entire offering should be an absolute maximum.