Yes, Penfold has good advice here. I apologize if my answer came off as sounding curt. I was hard-pressed for time when responding.
First and foremost this is supposed to be a fun endeavor, even in a stressful environment such as our upcoming regional championship. As these are people you may be playing with for a while (i.e. a recurring league night at Guardian Games), good sportsmanship goes a long way to ensuring everyone has a good time during this tournament season and the next.
Behaving in a manner that is "hardcore" or "cutthroat" - basically looking for ways outside the game to gain an advantage - goes squarely against the tenor of our community. This doesn't mean you can't play full tilt. It just means you should act like a gentleman while stomping your opponent into the ground.
Also, because everyone in the Portland area is relatively new to the game and each other, you're going to see a lot of cards being played that you've probably never encountered, and likewise for your opponent. Therefore, it is entirely acceptable to ask to see a card or for your opponent to do the same.
Having said all that, what do I do?
Whenever I take an action - whether it targets only my cards/deck or that of my opponent - I "talk through" what I'm doing. I'll say things like "I'm exhausting this character to do X" or "I'm discarding X card to activate Y card's ability". That sort of thing. For the most part I do this for my own benefit. As a bantamweight, after about half a beer I'm feeling pretty good, so verbalizing my actions helps keep me focused and sitting in my chair.
Overall, I think you'll find your games go faster when you give a brief explanation of what you're doing when you're doing it. You don't need to go into extreme detail unless prompted, but a quick rundown of your action to keep your opponent informed is both expected and appropriate behavior.
On a related note, it's important to give your opponent an opportunity to respond to your actions. If you sling out a bunch of cards, don't be surprised if your opponent asks you to stop, go back, and give them a chance to play a card of their own.