hh totally get where you're coming from.
But honestly, that body type drawn by Manhwa artists barely exists in real life (;´д`)ゞ. The 'paper-thin' figures in Manhwas are not only hard to find in reality, but they also often look a bit too slender/frail. Real-life beauty comes from proportions and a healthy glow (a healthy vibe radiating from within, based on physical well-being). (●’◡’●) Fashion is meant to serve your body, not for you to adapt to the clothes. Styles are diverse. Curvy bodies have their own voluptuous sexiness (like the Western/American style), chubby bodies have an adorable charm (like the Japanese 'City Boy/Girl' style), and stocky builds exude a sense of strength (like the workwear style). (But due to regional cultural influences... please make sure to point out any obscure common knowledge I might be missing. (;´д`)ゞ
Styling is essentially just an optical illusion. Based on the fashion tips I've picked up from surfing the web:
Generally speaking, having a solid/thick build is the case for most people, so I'll use that as an example (Pear/Apple body shapes): You need to use contrast. Wear lighter colors on top and darker colors on the bottom to balance your silhouette. Focus on 'structure'. Stiff fabrics (like denim jackets or structured coats) flatter your body lines much better than soft, clingy T-shirts.
Color theory is more important than size: Check your veins. Blue veins? You're cool-toned -> Go for Black, White, Navy, Emerald Green. Green veins? You're warm-toned -> Go for Earth tones, Olive, Cream, Brick Red.
Regardless of your size, wearing the right colors can instantly make you look 'expensive' and put-together. You should be able to find more extended tips shared by YouTubers.
Confidence is the best outfit for a lovely person. You got this q(≧▽≦q)~