Welcome, buddy!
Tips for PvP: it's matter of knowing what's most effective with the current rules and making a counter to that in case you face the most obvious strategies.
Useful links and tips:
Weekly PvP Tournaments, always on Fridays and Saturdays. The general rules are fairly simple, a tournament of simple elimination to a Best of 3 games. Every tournament has its "special rules", explained in the first post of each tourney.
Tip: Check the rules of the last couple of tournaments and then go to the last page, where people tend to post the decks they used.
Also you might want to read
This and
This articles.
PvP Leagues, there are 3 per year lasting about 3 months each. The rules are pretty simple too (mainly no card restrictions other than shards). There are some threads with collections of decks used in the leagues in the Decks Compilations topic.
This one is a VERY good read to know about good decks to see and the metagame.
The current one started yesterday ! ! !Many people also like participating in various
PvP Events, each one with their special rules.