As support, max R, W, then E, then Q. Buy the usual support items and pop your shield on whichever person (you or your adc) that starts taking the most fire. In teamfights, be near the front and be ready to use your ult to disrupt enemy ults and your shield ready for when you pop back out.
As mid, max R > Q > W >E and play more conservatively in lane. Buy some AP and some MR items to utilize your passive. Use your Q to harass, never your E unless you're going all-in for a kill. Hang near the back as AP mid in teamfights and ult after a good degree of damage has been done to the other side.