When choosing an icon, remember that certain icons already have certain meanings attached to them. It might be tempting to use a gear icon for a list of gears and machinery, but a gear is already associated with "Settings". Arrows should be used carefully - left and right arrows mean "Back" and "Proceed"; up and down arrows often mean "Upload" and "Download". Some icons can be ambiguous: a pencil sometimes means "Create New", but it often also means "Edit", so a plus icon may be less confusing when you want to add something new. Unfortunately, not even the most popular apps agree on what icons mean, and the same icon can mean something different to an iOS and an Android user. As with choosing the right component, the best way to make sure you've picked the best icon is just to ask someone with a fresh eye and do a bit of research online.