if it makes you look like youve really tried thats lame (i mean for normal wear. if you're going out then obviously you need to look like you've tried!). stuff that makes it look like youve tried too hard (for a normal day) includes painting nails, funny little dumb obscure adornments, anything non-casual / non-comfy.
fitted tops work wonders. what's printed on the tshirt, or what colour, is almost irrelevent, just as long as it fits a good shape. black fitted tops are even more sexy. skintight jeans make me cringe.
slutty stuff sucks in every circumstance (double meaning unintended)
i am describing nice clothes for girls who are good looking without clothes anyway. for those unlucky people who look worse without clothes than with them on, the advice will be completely different. for pretty girls, clothes embellish and attract and seduce; otherwise they hide and delude. its a sad world. but if you dont have a nice figure underneath, you're not going to want anything fitted.
i mean thats the point, these things we hang on ourselves are there to exaggerate whats good and hide whats bad (on a cosmetic level). the answer to the thread's question is "depends on whether you're hiding or seducing, whether you're sexy ANYWAY underneath or a bit lacking".
there's nothing uglier than a girl who DOESN'T have the figure/looks wearing something meant for someone much better-looking. i know its harsh but thats just the reality of it. adorning yourself just makes you look worse if the basics like your figure/skin/face/hair are yucky.