How I did it: i LOVE finding pennies, especially in 'unnatural' places. i strive to give others the same experience. my favorite place to hide pennies is on the gas pump while refueling because people stand there staring at the pump, and i put the pennies at eye level. they are never there when i return.
Lessons & tips: hide them alll!! make it a mini-goal to never have pennies in your change purse or pocket :)
Resources: i wish i would have counted or taken pictures of all of my great hides. i know there's been 43 (more like 430!), but i would like to try again someday and count/photograph them all.