20) Grind the dungeons when necessary.
Sometimes, you just will not have the material monsters necessary for a good power-up run. In this case, your best bet is simply to grind for experience. You’ll earn a ton of mana (the blue crystals) this way, too, which helps not only with power-ups to your monsters, but with powering up your runes.
19) Grind the hardest stages that you possibly can.
Your best bet for maximum experience is to grind the hell stages if you have unlocked them, or the hard stages if you haven’t unlocked them. The higher the difficulty level, the more experience and mana you’ll get, the more likely that you’ll get better monsters as loot, and the more likely you will be to get rarer and more powerful runes.
18) A cheat to get a lot of player experience points
This requires a whole lot of mana to do, but this is one of the best ways to get to the next level and possibly unlock another building. Build a bunch of large rocks (not the garden rocks) and then get rid of them. Each one that you get rid of will be worth 100 experience points. Clear out the rocks in your island itself before you do this, but then do this until you get to the next experience level.
17) Equip the maximum number of runes on each of your monsters.
Each monster can have up to six runes, so if possible, max out the number of runes on every one of your monsters. Power them up – it only costs mana to do so – but power them up as evenly as possible so that you get the maximum bang for your buck. The more you power them up, the more it will cost for future power ups, and the more likely a power up is to fail.
16) Complete quests to earn huge rewards.
Quests, missions and achievements will all earn you loads of mana, experience, and possibly even crystals depending on the quest, so if you are bored or you’re stuck on something and you don’t know what you want to do next, simply look over your quests and start completing them.