Hi and welcome to SDN,
You will really need clinical based experiences on your application. Here's why. The adcoms want to make sure you have been around a medical environment, you have been around sick people, you know what a doctor does other than what you see on TV, etc..... They want to be sure you have investigated the medical field and still want to become a doctor.
Case in point..... I volunteered at a free health clinic for 3 years. I saw many volunteers come through, big group usual in Feb and stayed till June just to put it on their applications. We had so many people that found out they really didn't like being around sick people, or patients that were homeless and smelled badly, etc...
Volunteering at free clinics give you a sense of what you will have to deal with as a doctor. smelly hair, stinky body odor, bad teeth and breath, people with no means to get the medicine you want to perscribe so you have to look for another pill that may not be as good but one you have in stock, young girls getting pregnant and not knowing what to do, families with no money to buy toothpaste for their kids and now their kids teeth are rotting,etc..... These are things doctors can face. Medicine at times is not a pretty thing like TV seems to show.
So that is why adcoms want to make sure you have been exposed to some things in clinical settings. Get your clincial volunteering done now and do it regularily. That shows dedication and is much more impressive than haveing 3 months of something in the 3 months leading up to applying. You can also do non -clinical things. There are some great things out there, meals on wheels, reading tutor programs, etc..., just make sure you have a good amount of clinical experiances, such as free health clinics, hospitals volunteering postitions, nursing homes, EMT, etc......
Good luck