The best thing you can do to grow your bitcoins is by gambling, or doing a signature campaign.
I would do a signature campaign because it may be slow but its profitable and its has no risks.
I think its not a way to grow your bitcoin signature campaign is a kind of micro job.. and its always profitable..
I will suggest that to grow his bitcoin its better to buy and ethereum because its still increasing and sell ethereum when the price of bitcoin is cheap..
So you can make lots of profit if it will happen..