50/50 Wins/Loses is about right for most players so don't worry about that.
The basic setup is Melee at the front, magic in the middle, and ranged at the back. The ruleset is key, if it's a 'slow', field your slowest cards, if it is 'blast', go for the fastest. If you can rent some level 2/3 cards I would save your DEC and try to do that. Good luck!
Thank you for the advice! is there a cycle of the combat styles I should know about? such as water beats fire, speed beats death etc? appreciate it thank you again!
I think they can all beat each other and it is the ruleset of the match that generally sways the result. If you are earning DEC via battle, i would take a look on the rental market for lvl 2/3 cards and see if that improves your win ratio.