I find it funny that people are so obssessed with trying to 'grow' their bitcoins. Bitcoins will do that naturally over time if you have patience. Don't do anything risky by investing in dodgy schemes and just concentrate on earning more bitcoins in whatever way instead.
We call it investment, which its the good way to grow your bitcoin with many ways. If we just earning it, then there is no difference between bitcoin and fiat. We can avoid any risky with collect all information about what kind of place or site we will invest.