To easily beat the Bird Man, use fire minions. They will make the process a lot easier. Just in case, have plenty of Mugorts ready.
Good Build up Area
A great minnion to battle for powering up is rashab in the spider forest find one defeat it and run over a couple of screens and go back it will be there again
Infinite Money
At the title screen hold L2 then press circle,x square and triangle. Go to a new game and you will have infinite money.
Level Raising Glitch
After you defeat Kikinak In the dragonfly Forest you can soummon him to fight again later, as long as you havent seen all the people in town turn to stone. the exeperiance you gain from him will always be the same and his powers will never increase, even if your minions are at level 30!
Lots of Mugwort Herbs
After you meet Koris for the first time in the Beetle forest, when he says he will train you, select "Attacks and Defense" and start training. He will give you a Mugwort herb. During the battle, on the first, second, or third turn ignore what Koris tells you to do and select a different command (except item) and he will tell you that you must obey. The fight will end and you will have an extra Mugwort Herb! You can repeat this until you have as many herbs as you like. Unfortunately, the item maximum is 20.
Powerful Water Minion
When you meet Koris in the beetle forest for the first time he says he'll train you to become a better cacoon master. In the list select "Capturing". Do exactly as he tells you and he should give you Apatron. Base your water minion off him to get the most powerful water based minion.