I can't comment on fat vs skinny but I am 5'8 and thin and I get cougars giving me the eye all day long. Just joined a gym so that might fix it, though I'll never be tall so that sucks. Want to attract some chicks my age rather than MILFs.
Most guys accidentally kill attraction before they even speak. They assume they need a bigger bank account, a better physique, or smoother lines. They miss the point.
Female desire operates on a specific set of psychological triggers. Break them, and you're invisible. Follow them, and you become magnetic.
I learned this the hard way. Years of freezing up. Getting friend-zoned. Watching other guys walk away with the girl I wanted. Then I discovered a set of 22 simple rules that rewired my entire approach.