A good way to minimize the risks is not invest real money (or invest a little amount).
With some efforts you can earn bitcoin from faucets, forum signature campaigns, glambling (not recomended), trades, etc...
After achieve a good bitcoins amount you could invest It. If you lose all, you don't lose your money.
i think is op want know about investment so is op want enough earning is good
faucet is not recomended, because very low earning
and must hard work is can get earning in faucet site