Get a friend with machines , and dig it to about an acre atleast around , then dig it to about 25 ft deep in the deep spot , but remember to leave some ledges and stuff that are shallower , then put a bush or two in there for cover , and soem tires or something , put rocks in a part of it at about 10-15 ft so you have it all , a rock bed , deep cool water , shallow water , cover , then throw in about 3 carp , 4 cats , some bass , trout , and even a few walleye if you want , but if i were you i would make sure i had atleast one fresh water spring feeding the pond , with a small stream to flow out , constant water movement is key in backyard ponds , you need them to stay cool and oxygenated!