Great! Well,
Step 1: Buy all German premium vehicles you can, from the warbond shop every season.
Step 2: line them up in a preset with +- the same BR.
Step 3: (if you have planes too, better): Use them in RB, trying to use the snail's bias at your favor.
Step 4: Every event (which happens 4 times a year: 2 crafting events and 2 Mark of Distinction events) sell the vehicles in the marketplace for a good price and use GJNs to buy premium vehicles and/or Golden Eagles and Premium Account. (By the way, this is how I bought Ka-50, the German Mi-24 superhind, and others). Note: With a 15 day premium account and grinding SL in helicopter battles with Ka-50, I researched ALL Russian helis and made over 10 million SL. In 15 days.
Step 5: Join a productive clan, and grind with them. Perhaps it won't be very pleasant, but it helps A LOT in your grinding, plus you will research squadron vehicles, which are OP and help with the grind.
Step 6: Enjoy!
Notes: I sold AGS in the marketplace and bought Ka-50. I sold F-5a in the marketplace and bought German Mi-24 superhind, and so on. I have dozens of premium vehicles, and bought only 3 of them with actual cash.
And, if you would like to, you can add me as friend and when chat is restored, we can play together! :D