yeah its very hard when you realize you get killed in 1-2 hits, but if you backtrack you can kill enemies and gain CP to upgrade your roles, gran pulse is pretty big, and if you backtrack there is a lot more to explore. just have fun exploring and doing cieth mission, then when you already kill te enemies without trouble you can move on.
There are some enemies, like Behemoth Kings or Adamanchelid (I still cant kill one of these things :lol )and Adamantoise, which can kill you in one hit, there is one spot at the end of the Archylte Steppe, where a Behemoth King and a Megistotherian are fighting each other, when you can do a pretty decent amount of damage to a behemot king, go to farm CP there, you can take them off guard, and stagger the behemoth king, and since it has 50% hp it should be pretty easy to kill, and then just finish the battle killing the other monster and they will give you 6600 CP, pretty good amount considering you can end the battle in less than a minute.