A scratch on someone’s face might be noticeable, while a scar that runs from cheekbone to chin would be conspicuous. When it comes to describing the things that attract our attention, noticeable means readily noticed or unlikely to escape observation (Ex.: a noticeable facial tic; a noticeable aversion to cocktail parties), while conspicuous implies that the eye (or mind) cannot miss it (Ex.: her absence was conspicuous).
Use prominent when you want to describe something that literally or figuratively stands out from its background (Ex.: a prominent nose; a prominent position on the committee). It can also apply to persons or things that stand out so clearly they are generally known or recognized (Ex.: a prominent citizen).
Someone or something that is outstanding rises above or beyond others and is usually superior to them (Ex.: an outstanding student).
Remarkable applies to anything that is noticeable because it is extraordinary or exceptional (Ex.: remarkable blue eyes).
Striking is an even stronger word, used to describe something so out of the ordinary that it makes a deep and powerful impression on the observer’s mind or vision (Ex.: a striking young woman over six feet tall).