Pay attention to what the quest goal is whenever you try to complete one, because if you build all of the requested tiles (numberwise) but you don’t build the right thing, you will fail the quest and you’ll have to either start it all over again or spend some ether in order to get more tiles or if you don’t want to spend ether, you will have to try the mission again.
Watch out for any enemy who ends up on top of a glyph, because that means you will have one seriously massive attack coming at you. When you see that happen, start using all of your shield moves if you have any, or your healing moves if you have them and you have injured party members who can benefit from their use.
Whenever possible, when you’re filling in matter, fill in the glowing gold tiles instead of the glowing blue ones. Most of the time they will only result in your earning one ether as a reward, but sometimes you’ll also earn a bonus card. Even just as feeder fodder, a bonus card is a great reward.
The more that you fight now, the less that you will have to fight later. If you find it to be a particularly easy time in the game, battle over and over again to load up on material. Fight until you have 100 or more Matter. Then use it to build tiles and blow through level after level, stopping only for the boss fights when you need to, in order to make rapid progress.
Take advantage of any special move that either places a curse on an enemy, or casts a protective shield on a team member. Protective shields will reduce damage taken by the indicated amount of power (check the card to see what the power is) every time that they get attacked. A curse does just the opposite, meaning that it adds the indicated amount of power (again, check the card) to the damage taken by the specified enemy every single time that they get attacked.
Save up your Valor Points and your Ether rather than spending them where you don’t need to. Then use them when you can afford to on the various boosters. Silver and Valiant boosters will earn you one uncommon, rare, or superior (or legendary for the valiant booster) creature. Premium versions of all of these will earn you a Rare, Superior or Legendary creature. The more of the same booster you buy, the higher the chances of getting its maximum-level booster will be.