You first need to reset the journey world over and over until u get a blessing that gives us +2 defense each time up use a defense move like protego. The u need to have protego maxima or protego diabolical. After that you need high damaging spells like sectumsempra. Everytime you get protego in your deck you need to use it because she always does 9 to 10 damage. And using protego maxima with the blessing gives you 11 shield basically making you immortal. It took me 2 hours to beat the ice queen with 3 hp left because they made her way too difficult without having any upgrades.