In the absence of experience against other good players who also want to play competitive army lists (the best way to get better), listening to podcasts or watching youtube battle reports CAN help a bit.
I recommend
The Long War
https://www.youtube.com/channel/UC3cEoZV1BsBLeJy5LxGNRtw
Frontline Gaming
https://www.youtube.com/user/Team0Comp
and one I recently found that appears knowledgeable, but I've only listened to a few episodes
TFG Radio (look it up on Itunes, or you can listen on the facebook page)