Various General Tips
When transferring game data from one phone to another, make sure you use a WiFi connection. You wouldn't want this to use up all your megabytes.
There are 4 main types of attacks, based on the tile color: white, purple, gold and blue.
White tiles are basic and the weakest attacks; then come the purple tiles which have special effects; then the gold tiles and, in the end, the blue tiles that also offer you defensive moves.
Always keep an eye out for corners of the board. If an opponent corners your creatures, you will lose them.
Pokemon Duel games are designed like chess games in that you also have a timer, so you can't stall and force your opponent to lose by disconnecting.
Focus on blocking your opponent's spawn points, so that they can't bring Pokemon back into game. If you manage to keep your Pokemon there, you will be able to win passively, just by not moving.
You can pay real money to get Boosters to help you out, or you can use either locked or timed boosters. You unlock the locked boosters by collecting key fragments, while the timed boosters unlock after certain amount of time.
The Quest Mode is great for acquiring some more Gems. All you need to do is remember to enter the challenge mode (marked with three golden stars).
If you're just starting out, it's a good idea to do the training missions first. Not only will they show you how to play properly, but they will also give you gems and plates.
Use your Pokemon abilities wisely. They are all unique and can make a huge difference in the match.