My advice has always been to take a deck type that you find fun and has enough cards on both sides (a lot of T1 decks don't use a lot of defense, and the ones they do may not always translate; spread doesn't work quite well in T2, try to stick to themes and/or brigades). Then, put in multiples of the most powerful characters (uniques should generally only have 2 per, with 3 per for the most important characters that make the deck), and then 4 of each of your best enhancements. See where you sit, and start paring it down by removing the least powerful until you strike that balance. Play with it, see how it does, swap cards, and let it evolve.
Honestly, learning good T2 deck building doesn't happen without
playing T2. When I started 2 years ago, I built a deck based on some fun combos I saw and thought it was pretty good. However, over time, the main focus of the deck changed dramatically, as did the way I built decks in general. I used to advocate for 112-card decks so I could fit everything in, now I'm down to 100 in all my decks for the speed and to focus the power.
If you are looking for specific combos that at least run in T2, Genesis/Egyptians, Disciples/Prettymuchanything (Pharisees work well), Judges/Alotofthings (I like Canaanites), Isaiah-Angels/Assyrians, and Ezekiel-Prophets/Babylonians are decent in most versions and generally have good combos that let you learn T2 strategy. Look around on the boards and you will find plenty of decklists for those (and other) themes
