You can grow your tbc when you invest for some site that realy are paying in return, but be careful theres a lot of investing site now that is a scam. Also you can buy and sell btc, this is the time to buy btc while the price is still low because sooner or later it will get so much more expensive. But take care also because there are lot of scammer now. You can also gumble with your btc it is an easy way. But ofcourse there is no assurance if you can win or not. You can trade something in exchange with btc. There is a lot of way to grow your btc. Don't just keep it will not grow without running it.
I think you are saying that you invest it in investment site honestly there is no legit investment site almost all are scam you dont need to be careful you should stay away from them and also in cloud mining site they are scammers..
For me if you want to grow your bitcoin the best place is trading where you can trade for buying low and sell high just like other do right now..
Trading is the best method to grow your coins no doubt there is also an risk of getting negative income if you make a wrong move but after gaining knowledge and experience the risk can be minimized and you can bring positive results out of it and as of now we cannot afford to trust any online sites for investments as there is no sure shot guarantee that it will pay us for the money we invested.