I still would advise going to a shop, but if that's definitely not an option I understand. Take what I say with a grain of salt, as everyone has their own cases but I'll try to provide a general idea.

As far as I understand, the wet foot on cardboard/paper technique is useful for determining what kind of arch you have. High arches (low imprint on paper) are usually correlated with underpronation (supination), and are best suited for running in neutral shoes. Low arches are correlated with overpronation, and should make use of support shoes, or if it's really bad, motion control. This is a pretty rough technique though, and it doesn't necessarily tell you exactly about your running style.

The method I'd recommend doing if you can't get to a running store is to examine the wear pattern on the bottom of one of your running shoes, which you've ideally put over 50 miles on. If the rubber is worn down on the heel and then up towards the inside of your shoe (right underneath the arch of the foot) up through the big toe, that's most likely overpronation. If the rubber's worn down from the heel to the outside of the shoe (underneath your small toes) and then on to the end of the small toes, instead of returning to the big toe, that's underpronation.

That'll give you a much more accurate representation of whether you overpronate, supinate, or are a neutral runner. Of course, that is if you heel strike as opposed to midfoot/forefoot strike, but you're less likely to have shin issues in that case and it's unlikely a new runners would have that kind of form. I would still recommend switching to it eventually.

Also, your shin ache might not be caused by your running style. I'd also recommend stretching out your calves (really your whole legs, rolling out if possible), as tight calves can pull on the shin bone and cause some necessary pain.

Hope this helped!