Title says it all really, have tried a Mage, yawn. Tried an assassin which is fun, but also want to try a sword and shield type warrior. I was just wondering if I could get some general useful tips on how best to play and learn it.

Otter.

It hits things with the pointy thing and blocks things with the flat thing.

Seriously though, just watch what your opponent is doing. If he's about to attack, put up your shield to block, then quickly counter attack. Not much else to it.

This!

Thought as much, I just dunno about the heavy vs light armor yet since my shield sold be taking the brunt of all damage directed to me.

theres a perk in block you can get at 40 block skill i think...might be 30. its the perk sticking out in the middle of constellation. it slows down time when ANY enemy in the melee range is about to land power attack.

block is good for regular attack, but enemy power attack negates your nlock and make you stagger. thus this time slowing perk lets you effectively deal with enemy power attack whether by dodging it or bash your enemy before he lands that blow.

long story.short this perk is the most important and coolest block perk imo. then you can pretty much ignore block perk until you hit level 70 when you can finally get perk where you move.fast even with your shield up. by then you are quite versatile in art of shield.

Is it possible to stagger a power attacking enemy with the time slow? I have tried to normally but it's a bit hairy xD

yes the timing to interupt power attack is really tricky, even with time slow it's hard if they use a one handed sword you most likely won't even have time to bring up your shield before they hit you, even less interrupt them.

Shield bash to the face?

Bash. It's great, when you see your opponent strike, or cast hit him with the shield, hack him, repeat. If there is too great distance between you and a target using bow, or magic use the dragon shout that allows you to sprint up, or whatever that is.
Didn't try the slow mo perk might be fun, but with well timed bashing few enemies manage to land succesful blows. Also bash breathing dragon in the face, looks cool how they recoil!

Tried bashing the first dragon the face. I still get chargrilled since I'm on expert atm but it did stop be being turned to a smouldering heap of charcoal.