Does anyone actually mine. I do but I find it's really hard to find something to mine. Is there anyway to tell if you can mine a wall by looking at it? Is there mining available in every dungeon? I do want to mine more but can't seem to find where to do it.

Tip: instead of going up to the wall and pressing activate x (ps3) just equip your pickaxe and swing at the wall. It makes it much faster instead of sitting there waiting and watching your character. It also makes it feel more real.

You can usually see an ore source because it appears as rock streaked with a metal, usually fairly shiny. As for me, I've always got a pickaxe handy, and I come across ores in various cave areas, as well as mines, of course.

You know, I have ran across more ore going from point A - point B on quests (including discovering mines),
than I ever did actually looking for them.

You best bet would be to make a full Iron suit & weapon early on, play the game, and mine ore as you run across it.
At least until someone posts a very detailed map of every ore deposit in Skyrim... at the moment the wiki is not anywhere
near complete enough to show all the mining locations.