If you watch ads (tap the Television icon from the main menu), you'll be rewarded with superior loot drops. You can watch as many as three videos in short order, and they will increase the quality of cards and the number of coins you receive for as many as four hours. If you're going to be playing for a bit, anyway, it makes sense to start your session by viewing some ads.
Be Thrifty with Gems
You can spend gems on a variety of things, but many of those are a waste. Ignore the option to speed up research, and instead spend gems to obtain rare and epic card packs. If you're running out of gems, check the Quests log to see if there's a way to earn some more. Gems are your most valuable resource, so the goal is to obtain as many as you can and to spend them where they'll do the most good.
Combinations Matter
Make sure to combine cards when they can produce something more powerful. Check out the research portal, where you can unlock new ways to combine cards into one. Combined cards can become tremendously powerful, since their attack and health stats are equal to the total of the two cards that were combined.
Monitor Your Deck
As you continue your quest for cards, you'll frequently obtain new ones that can improve your deck, but they'll only do that if you actually stay on top of things. Always check any new cards you gain, to see how they can affect your deck and determine whether they will enhance it compared to the cards you already have in active use.
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