According to our resource, Crotons (Codiaeum) normally stay somewhat compact and bushy on their own and therefore don't need pruning unless the plant gets too large.
Without a photo or further details we wonder if maybe it is not getting enough light, which can cause elongation as it reaches for light and/or premature leaf loss. Some lower leaf loss with age is normal.

The good news is that you can cut them back as much as required, with the best time being now in early spring, and yes, above the node is good. 
These plants will 'bleed' white, sticky latex from cut stems and you can lessen this by spraying cut ends with water or putting a small piece of paper towel over the cut. (If you have a latex allergy talk to your doctor).
As far as light needs, they want bright light with at least two or 3 hours of direct sunlight for best coloration.

Christine

You're welcome. We are happy to help.