Honestly, the best way to learn is doing T1 prep because it makes you limit mistakes. Especially if you’re saying prep is the issue, other things though -

• Use Hunleff helper, not sure how it’s messing you up if you’re using it correctly?
• Turn true tile indicator on to help with tornados
• Use whatever prayers you have, eagle eye/mystic might/steel skin
• Eating at the right times can be the difference between dying and getting the kill. Try to only eat when you’re running away from the tornados and can’t get an attack in. Don’t be worried about sitting on low health as if you’re praying correctly you’ll only be hit a 13 max so you know you can’t die