Either by finding/buying an amulet that gives it to you; I'm not sure if any clothing items that give it. Or you must be a Balance Wizard; not just have it as a secondary school but as your main school.
Well, you have to be balance. If you're not balance, you must be level 25 to get boots of the elements from the boot shop in marleybone. You must use crowns to get these. Also, a pet called the gamer piggle has it. You can get this from a gift card (I forgot where the card is from).
I see where you can get the spell for 3 blades or 3 traps. where do i get 3 shields spell from?
You get the spells from the Balance Tree in Krokatopia. If you're not using a Balance wizard, it'll cost you a training point for each blade or trap spell you purchase. Also, they're dependant on what level you are, before you're able to obtain them...
I suggest that you only get the blade/trap that has your school (you don't have to buy all 4 spells, just the 2 you want), and then use your other training points to determine what secondary/third school you're wanting so the blades are more 'efficiant' for you in the long run.
You get the trap for fire/ice/storm at level 15, the matching blades at level 25.
You get the trap for life/death/myth at level 20, the matching blades at level 25.