If you want to look taller or slimmer, you need to use the unbroken line as your guide to dressing.
What is the unbroken line? Every time you end a garment, and the hem of each garment creates horizontal lines (which break up your body), you are shortening and widening yourself.
So creating an unbroken line by using a column of colour from shoulder to knee (or longer) will elongate your body.
Don’t forget to colour blend shoes to your bottom, or to your skin to create the longest, leanest lines.