Think about where you will be going on your workout before selecting push ups. It will be easier on your hands if you can do your push ups on grass.
You can choose your own type of push up which relates to your level of fitness and how hard you want to push yourself.
Here are some links on how to correctly and effectively do a push up and some push up varieties to keep your workout varied.
http://www.nerdfitness.com/blog/2011/02/15/proper-push-up/
http://www.keepinspiring.me/10-massive-benefits-of-push-ups/
http://www.bodybuilding.com/exercises/detail/view/name/pushups