Definitely include your total clinical clock hours of direct patient contact and break it down into what areas you've had hours in such as pediatrics, adults, diagnostics, hearing aids, aural rehab, balance, etc.
Be sure to list what hearing aid companies you are familiar with. Find out what the place you are interested in your fourth year dispenses. Learn the products. Read the white pages and research behind the products.
Research the people on staff. Find out what their interests are. Remember you are telling them why you should be chosen to join their team. Why are you a viable person to train and mentor? If you are interested in vestibular testing or auditory processing disorders and a certain staff member does that as a major research or clinical interest then state that in your cover letter and in the interview.
I was floored by a student who contact me once for a possible summer placement.
She knew what research I had done. What my clinical interests were. What hearing aid companies I sold.
I was impressed. She had done her homework.
Remember getting a fourth year is just like landing a job, only harder because you don't have the experience under your belt to sell yourself. Tell them why you are someone they would want on their team. I landed my fourth year gig because I was always willing to drop everything and work the front office if there were no patients to be seen. I was doing billing and calling pt's and scheduling them. Updating advertising stuff for the clinic I was in.
These are all things people look for in their 4th years. Look at what skill sets you apart from the rest of the pack. And then run with it.