The kanji 火 is pretty easy to memorise, it’s basically a pictogram of a fire. Remember the bonfire you light on camps, the small flickers of fire flickering, that’s the kanji 火!
The kanji 高 looks like a tall pagoda building. However you can also memorise it an item placed on a high shelf on top of a table. You need to be really tall to be able to pick it up 😉
Lo and behold, there is a cute girl before me!
The original kanji was 歬 which was a compound of 止 and 舟 which means “a foot on a boat”.
The kanji 休 which means rest is an ideogrammic compound of 人 – man + 木 tree. It’s basically a man resting while leaning against a tree, pretty easy to memorise.
From the ground a tree grows up. This is how you remember the kanji 土, there is a tree growing up from the horizontal ground.