there is no safe way to grow your bitcoin, because they all have risks.
but you stay focused on the signature campaign, if you want to be safe without risk.
Indeed, staying focused on the signature campaign was proven and tested. I also do believe that everything in bitcoin currency will always have a risk to any member here, meaning you must be a risk taker at all anyhow.
You will never gain higher rewards unless you don't take higher risks and if you cannot afford to take risk then the safest way to grow your bitcoins is from signature campaign.