The next rule to adventuring, stick to the surface for the first little while. Again, they aren't all going to be hostile, but the ones that are tend to be very well armed and will swiftly put you down. While adventuring along the surface make sure to use caution if you spot any creatures, but be extra careful about approaching NPC's. Although this isn't always the case, it is a good rule to follow that will help extend your life during those early times.
The first rule to exploring in Starbound is to assume that everything is hostile.
