I recently began watching Matt Colville's D&D videos on YouTube. As well as his campaign diaries and assorted other topical discussions he has a series called Running the Game. Running the Game is both interesting and educational, full of great advice and ideas for use in your game. While the series is primarily focused on the current 5th edition of D&D, the ideas and DM techniques work for any edition.
I highly recommend Matt's videos for novice and veteran DMs alike.