If you don't have capital to invest in trading then to build up your capital you should start your journey with signature campaign and whatever bitcoins you get from it should be saved until you don't reach to a decent capital and once you have good amount of bitcoin in your wallet you should start trading with it to grow your bitcoins much faster.
This is a good idea for those people that don't have money to invest or trade at the start. I myself was doing signature campaigns and when i earn. I used that money for my trading activities which helps me a lot today. So for people go for signature campaign first if you want to earn first without spending your savings.