I still suck, but this was the order of DGs that I played:
*couldn't decide, so picked any ole one* got raped.
*tried UB (he's all the rage)* spit, retreat, spit retreat.... ok getting the hang of it!
STOP CHARGING!
*continued with UB, discovered that +health and +speed are not the only useful favor items*
*tried out Rook* Get +HP favor and +HP armor, and +armor and go full HP and towers, then kite and let your teammates kill
*sprinkle in some boulder and slam with rook*...ok now you're getting it
*try out reg* snipe.
*try out reg* mines.
*try out reg* distance + slow + snipe + BotS
*try out erb* pick any build. own.
Just learn those guys, then branch out to the others. You'll find the most rewarding DG is QoT because she is very difficult to play (other than bubblebot)