The question asks you to determine the force in CE, so you can do that using either the Method of Joints or the Method of Sections. If you look at the Method of Joints, about either C or E, you simply don't have enough information to solve the question. You could probably pair multiple Joints in order to generate more equations, but it's simply unnecessary for this type of question.
With the Method of Sections, you need to minimise the number of cuts (i.e. you should not have more than 3 cut members), minimise the number of unknown forces (especially due to the cuts), and maximise the use of known forces.
So in the above example, we obviously need to cut member CE since that's what we want to find out. So the next cut will either be CD (then through to BD) or DE (then through to DF). If we look at the latter, you would probably take moments about E and analyse the right section, but you would need find the vertical force at H. It's therefore better to cut through CD and BD, since that gives us the optimal amount of unknowns and knowns.
It takes a bit of practice to recognise when you should use Joints or Sections. Aim for the least amount of unknowns and it's likely that will be the best method.
