My Amazon Echo skill was recently approved by Amazon. You can enable this skill by saying this on your Amazon Echo:

 "Alexa, enable Chicago Food Truck Finder skill"

Some things you can try:

 "Alexa, Ask Food Truck Finder what food trucks are near Willis Tower today?"
 "Alexa, Ask Food Truck Finder to tell me about Doughnut Vault."

 "Alexa, Ask Food Truck Finder what food trucks sell tacos"

 "Alexa Ask Food Truck Finder what food trucks sell Korean food."

 "Alexa where will Cheesies be for lunch?"

The proximity skills such as (where is XYZ for lunch?) work better closer to lunch time when I have a better idea of the daily schedule. If you ask about Doughnut Vault it will give you the daily specials (if it is known at the time).

Also, I appreciate feedback and (especially) good reviews via the alexa app or the Alexa Website.