I first learned the 57" rule on Apartment Therapy three years ago and it's helped take the guess work out of how high to hang anything in any space. 57" is the average person's eye level so galleries tend to hang art work at this height.
DIYに便利な「タッカー」使い方と実用例まとめ | iemo[イエモ]
Easy DIY Wall Panels . These panels are made of foam board w/ fabric wrapped around. I originally created this idea for a problem oblong wall