1 Earth = Venus
2 Earth = Ramses
3 Earth = Cybele
4 Earth = Judgment
1 Fire = Mars
2 Fire = Kirin
3 Fire = Tiamat
4 Fire = Meteor
1 Wind = Jupiter
2 Wind = Alalanta
3 Wind = Procne
4 Wind = Thor
1 water = Mercury
2 water = Nereid
3 water = Neptune
4 water = Boreas

aftering summoning, Djinni will need to "recover" and you won't be able to use them for a turn or two. You can also walk around after a battle to let them recover. After recovering, Djinn automaticly go back to set.

Tips on battling and finding
i usually match the types of Djinn with my characters type because you get the most power. A Wind element Djinn for example, will raise the power of your wind type attacks and also your resistance to wind based attacks. There are some exceptions tho, so try trading Djinni and making new combinations and strategies!

Also be prepared for tough battles (such as boss battles) by putting a group of Djinn on standby so your ready to summom on the first turn or two. This is very usefull when trying to defeat other Djinn, because Djinni have a habit of fleeing the fight. If they do succeed in getting away, try leaveing the town, forest, dungeon etc. then returning for another chance. Don't forget the weaknesses of each type too. Naturally, water will be strong againted fire..and such...djiin are really cool to have in the game...I suggest you always take care of them!