Basically the only games I've made time for in the past few weeks are Destiny and Hearthstone, and I could always use pointers on the latter.
I'd recommend picking one or more Youtube players to follow, some are really good teachers and have good tutorial videos, namely Kripparian. Gameplay wise, much is about card value. Cards like Sludge Belcher and Piloted Shredder have really good value because you get the most use out of your mana.
You could also play a few arena games with the help of an arena deck builder helper like arenavalue.com. You tell it which cards Hearthstone is letting you pick from and it tells you which one it thinks best out of the three, often even explaning the reasons for its choice. That way you learn while playing and getting your hand held.
I haven't played in a while, but I'm fairly good at card games. What kind of pointers were you looking for?
Also somewhat casual, long time player. If you want to get better, read a few deck guides first, but don't be discouraged by your lack of rare, epic, and legendaries. Secondly, if you're striving to be competitive, you should unlock most tiers of Naxxramas and the first tier of Blackrock Mountain for Emperor Thaurissan. I can't remember if arena still gave GvG cards, but it is the most efficient way to get cards/gold. Still, I just like to open regular packs. We'll make plenty of mistakes when we play, but learn from it