MTG Salvation

I am a new player and recently bought a bit of intro packs. I know people say that they aren't a good deal but I was able to pick them up for $8 each, so I figured that was well worth it since they came with 2 boosters each. I am looking to upgrade then into somewhat playable decks, because they just don't cut it on their own. As I've said, I am new and don't have much knowledge of existing cards to add, so any suggestions for upgrading the Eldritch Moon or Oath of Gatewatch intro packs would be greatly appreciated. Thanks