If you hold a single piece of your hair up and look at it, does it seem like it's kind of hardly there? If so, it's fine. Or is it a bit more substantial yet still bends easily? It's probably medium. Coarse hair looks very wiry, substantial, and sturdy. Also, you can read this link for more information:
science-y hair blog: Is Your Hair Fine, Medium, or Coarse? How to Measure
I used to think I had medium-to-coarse hair, but I was completely wrong - I have a good amount of fine hair. Sometimes density and texture can be confused like that. It's also possible to have a mixture of textures on your head. Another way to tell if you have fine hair is that it often "dents" easily - i.e. if you wear it in a ponytail and take it down, if you can see exactly where the ponytail holder was, you might have fine hair.

If you feel like you're getting overconditioned, I would add protein into your regimen (assuming your hair is ok with it). Also, I would recommend adding in a sulfate-free low-poo at least every few days.

Frizzy-ness can be caused by different things - including product buildup on your hair (a good reason to rotate what products you use each day), dryness, ingredients that don't agree with your hair or with the current weather (for instance, glycerin and my hair do not get along), not enough gel to tame the frizz, too much product, etc. It will probably take some trial and error to figure this out.

As for styling, I have best success when I rake/comb a tiny amount of leave-in through my hair, then get it sopping wet again by scrunching handfuls of cold water into it, then flipping upside down and scrunching a curl enhancer followed by a strong hold gel into it. I scrunch and scrunch and scrunch a lot to really get the waves/curls going and the products distributed. It should be very 'squishy' sounding. Then I flip back upright, maybe scrunch a bit more, and let it dry. Now that my hair is past my shoulders, I usually plop for ~10 minutes to pull some of that moisture out and help set my curls and speed up drying time a bit.

Hope some of that helps!