The word 「よう」took me a while to understand because it's kind of an abstract concept. It doesn't have a direct translation in English; if I had to take a shot I'd say it's something like "a situation or state of/where __"... The only way for me to understand it is in context. One place I hear this word often used is on the train when the conductor says "Be careful not to forget any of your personal belongings."「忘れ物ないようにご注意ください。」To directly translate this would be something like "Please be careful for a state of no forgotten things." That sounds pretty strange worded like that, but if you think about it it makes sense. The train conductor wants an end result of "no forgotten things" and for that purpose he/she would request that you be careful not to forget your things.

Entering the previous sentence in Google translate yields this: "Please note as not left behind."