my "rules" for me, in case they work for anyone else:
avoid crinkles. hang things on hangers while damp (even tee shirts) to minimise ironing. garments with a little elastane are worth having. something a little fitted or tailored is inherently more flattering than something baggy. i say this as a size 18 apple shape with a podgy belly.
dark jeans are always more flattering and more glam than pale jeans.
find a jeans / trousers style that suits you and stick to it, even when fashion decries it. i need a low-waisted boot cut, and have longer pairs to wear with heels and shorter pairs to wear with flat boots, ballet pumps or flip flops, depending on the weather.
keep it simple. generally i will wear eye catching earring OR an eye catching necklace. not both at the same time.
use accessories to guide people's eyes away from the bits you want to hide. i tend to hide my belly by wearing plain tee shirts (black or white suit me best) and use a necklace or a great pair of shoes.
a little make up to even out your skin tone, calm down any shiny areas, and emphasize your eyelashes.
takes me about 10 minutes, another 5 if I want to straighten my hair too. GHDs are wonderful.