First rule of offense: No deacons.
First rule of defense: There are no rules for defense.
Since you have been playing less than a year, I'd say the most important thing is to find out what you like. Follow the above two rules and you should be alright using colors you are comfortable with. A friend of mine's main deck is still silver and crimson (crimson mix of magicians, animals/Esau, and N.T.) and it still can win games.
Karius' deck is a great example of synergy. Obviously some things will pair better than others, and you can usually get good ideas from the deck advice section. Just avoid doing something like using Nazareth in a philistine or judges/prophets deck, Three Nails in an orange deck, or using Romans Destroy Jerusalem alongside a purely N.T. offense. That would be silly.
Another morsel of advice: If your offense is slow, consider a fast defense, and vice-versa.