If you want to die less, then recall more.

If you want to die even less, afk on fountain.

I did this once and I had no deaths that entire game.

If you want to die less then do less stupid things. Recalls are like mini deaths. It's time away from gold and experience. It's the same as dying except you don't give enemy gold. Recall enough and the time spent recalling and walking back adds up. Had a friend try this a while back and he racked up about 8 deaths worth of off the field time. Hard to carry games when you are under leveled and lacking in items. The trick is to actually recall as little as possible and only do it for power spikes. Mid and late game if you have an advantage you want to not recall athe all if possible do you can pressure and deny.

The key to immortality is...

Not dying.

Just stay in your base. You'll never die