When I finally get inside fashion design school, I was so excited, but I find out I don't like to design most runway show that dramatic design, I'm prefer really simple and won't out of date kind, then I just fall in love with Japanese style design and culture, since then I was making most of my clothes follow this simple rules, which you can start to make your Japanese style dress/ shirt.
Most of them use Linen and cotton for their main material, I love linen so much, even they get wrinkle a lot, you need to iron them quite often after you wsh them, but the wrinkle part is the charm of the linen, they just record you basic movement. And each time you wash them, they just turn more soft and beauiful.
(Picture from: google imagine search)
Follow the nature and earth color, then you won't go wrong, they kind of low key, but have their own personality.
Aftern material and color, then the most inportant is fabric patterns, most the time I like the plain kind, so later I can add some embroidery on it, to make your special own design, but you think is plain design is too boring, then follow the nature rules, find little design of trees. flowers, mountain, check, stripe those kind of design then you won't go wrong.
Then you find you loveing material for your new project, now the key is patterns, most of Japanese style dress is pretty lose and kind of baggy, so you wear more freely, so they can hide of little belly (kidding)check on this two design then you will know what I mean.
Japanese style design looks simple and easy but most of their beautiful things is little detail you need to find them out when you get close, maybe is a little folder, little nature wood button to light up the design, so don't miss this small detail will make your design to next level!