I'm still a very newby deck builder in redemption, but do have a few years experience in other TCGs, and with our limited collection a few things I have found are a fun solid defense are:
1) trying for low abilities on the ECs to gain initiative and then using capture or destruction cards (e.g. Seige paired with King Zimri or Deceit of Sapphira is fun, Wrath of Satan also works, different Archers are also useful)
2) Along similar lines, using low EC abilities to gain initiative and using lots of discard cards to gain card advantage on your opponent is also fun (there are some cards that even let you look at an opponent's hand and choose a card for them to discard)
3) The other thing that has worked is using larger ECs that are immune to things and/or backing them up with various negates and interrupts in preparation for anything an opponent may play when they gain initiative.
Hope some of that is helpful, God bless.