Think I've said this before, not sure.
For anyone new looking to gain skill, dewyunchained streams on twitch at night time. He's really good and I've learned a lot from him.
He is typically a fast rotation deck player. From playing at high rating I've found the fast decks seem to force you to really gain skill that helps the most. Placement, how to learn opponent deck and start playing around it, baiting, etc.
It's a lot harder than just dropping a big push every cycle and hoping for the best, as I've been guilty of a lot.
Also, it seems like beyond spending money you want to:
Keep chests unlocking 24/7
Try to time 8+ hour chests to start before bed
Keep up with crown chests
Always donate unless it's a card you really want in your main deck long term. Getting experience from donations was a huge part of how I got level 12 so far. When in doubt, donate and don't look back every chance you get.
Always request cards when you can, you'll max out on Commons long before rares ,epics ,or legendaries, so may consider requesting rares instead, and epics when you can on epic sunday.
Join a clan as soon as you can to do this, and then join the forum clan Hogan's heroes when you have enough rating for entry.
Click the TV button, scroll over to legendary arena, and watch the replays from guys in the top 200, you can learn by watching them too.
Having all commons maxed, I still get tons of them in chests, and little of what I actually need. If I knew that I'd prob been requesting rares the while tine instead of Commons. Unless you're really need and knees a decent level set of Commons.
Lastly, once you have a deck that can be max level in the grand tournament, you have equal level cards as your equal level opponent. No over leveled cards smashing you, purely skill. This seems to be where you can learn a lot and become very good. The rewards are also super great if you can win. This is probably the best card grind alternative if you can win decent number of games regularly.
Hope that helps