From a Leaving cert student. Just speak an write it as much as you can. If possible have small conversations with your friends on the way to or from school. Perferable sokeone good at the subject so they can correct you. Learn the verb ending eg o as a amos ais an for presant tens ar verbs. Learn all verb endings. As for the listening learn numbers they always seemd to come up. But most importantly dont worry too much its the JC and it doesnt mean a whole lot.
If you ever feel stressed or worried just feel for us 6th years who need to get X points for college.