Always cite sources that use .org .edu or .gov
try to avoid sources that have excessive amounts of adds, pop-ups, or end in .com or .net
try to cite from peer-reviewed scientific journals if possible
make sure the information is not outdated
always make sure that the source you are using also cities where it got its information, and check those for validity.
For this particular prompt, it is a good idea to look at studies and government information.