Growing bitcoins can be done by using multiple methods or one good method in my opinion, I only do signature campaigns because they have a learning factor, are fun to do and also profitable without any risks plus you will grow your bitcoins.
Other than doing campaigns I do trading sometimes although I think its pretty risky so I do not do this often.
Soo you making almost the same thing as me my main income comes from signature,that is put at poloniex and making my coins grow slowly soo its always the best ,i love poloniex and their service .
Yes indeed to grow your Bitcoins safely you have must have a signature but you have to know that it can takes a long time until it will be more because it happens not that fast.
Patience is really important or you can also even trade or gamble but that is more riskier.