I'm an RN working in Psych currently (and I just accepted a Med/Surg position in a new hospital actually) but during nursing school
I worked as a CNA on a Med/Surg floor and I felt that I definitely learned a lot while I was there. Keep in mind that every state has their own scope of practice for a CNA (as it does for nurses) and every facility has their own policies and procedures which will dictate the tasks that you will do as a CNA. On my unit I did the following: obtained vital signs, performed blood glucose testing, obtained EKGs, performing phlebotomy, assisted patients with ADLs (feeding, bathing, grooming, dressing), ambulated patients around the unit and emptying foley and ostomy bags (those are the major things.) If you can try to listen to the nurses you work with and offer to help whenever you can, this will really help when it comes time for nursing school. If you work on one floor regularly and show a good work ethic you will find that most nurses will really appreciate it and they will be happy to teach you things that are helpful in nursing school. If you can, try to find a job at the hospital you're doing clinicals at because you will have a better chance of getting a job there as a new CNA (otherwise you may have to get some experience in LTC first). Best of luck and let us know how your clinicals go!