Rule number 1 only buy off established reputable dealers such as...

Rule number 1 only buy off established reputable dealers such as Ainslie, ABC, Perth Mint and the like. There are loads of stories of people being ripped off with fakes.
Rule number 2 kilo bars are good. ounce coins and rounds are ok but premiums will take a while to be absorbed as there is a big spread on the buy and sell.
Rule number 3 store them safely and carefully. Accessible but not necessarily at your home. Probably best not to use bank safety deposit boxes as it adds another layer of complexity.