Investing in real estate and gold is good enough in my own opinion. Stay away from online investments. Most of them either are scammers, get hacked, or simply disappear. Also make sure to invest only that amount of money which you are willing to lose and make sure to get back the capital. You can also try altcoin trading.
Gold investment is for safety but there is still risk if you are invest a lot of money and gold.. if someone who knows about it they can thiev and steal it to you that may risk your life.. so for me its more safe to invest money in bitcoin and hold it for a long time..