Each persons selection of tank types - those being light, medium, tank-destroyer (sniper), heavy, and self-propelled guns (artys) - is an individual selection as to what they prefer. Me, I have enjoyed playing the arty lines because it's slow, its un-appreciated, and it can really save the game IF you know how to play it. So let me offer some tips from my perspective.
The advantage I get from playing arty is that you can look down from above and see how everyone plays ... what works and what fails. That perspective will help you with other tank lines. Yes, watching QuickyBaby on Twitch also helps, but you gotta jump in and try yourself.
So, what works ... for me.
When I'm first getting into position, I look to see if there's a bunch of trees in my area. Because if there is, if I need to re-position, I don't need the red arty seeing trees falling and knowing where I am. So as I'm getting into position, often I will knock down most of the trees around me because at the very start, few pay attention to falling trees and you can do that with impunity. Take Prokhorovka as an example ... from North or South spawn points, on the west side of the RR tracks are lots of trees and I like to park in there ... and move around if I got spotted. By dropping the trees in my area at the very start, I can move around with impunity during the game as they will never see any "indicators" as to where I moved to.
Now that the shells are less accurate and less deadly, you have to select your targets carefully. So when someone is in a scrimmage with an enemy, you need to be thinking about both your lead times (cause those shells arc WAY high) but also where the enemy is going to go. When he starts to receive shots, typically they will hit the REVERSE key, so aim behind. Also, watch him for awhile if you can ... sometimes they will go FWD/REV/FWD/REV so you will need to shoot to the middle of them.
One advantage of watching the game unfold is that you learn where people always perch / snipe. So at the very start, I usually put at least one shell (called a blind shot) into one of those areas ... and get about a 33% hit rate. Even if I don't see it HIT something, I suspect that at least 50% of the time, I cause damage to an enemy.
Another aspect of "watching" is knowing where to point your arty where you know the enemy always advance ... pre-aim or "getting ready". If you don't get ready, your reticle bloom will delay your shots by 20 or so seconds while the reticle calms down.
Change targets ... hitting someone on one flank, them moving to the middle gets them to all be careful because they really don't know where your aiming, so all of them think "he could be aiming at ME".
Stop being an arty ... when the game is getting down to the final tanks and being an arty isn't of much value (map depending of course), put yourself in an aggressive mode and go and harass the enemy. A few days ago I had two instances where I did this. In the first case, I rolled in front of the enemy to distract them ... yes, I died, but my teammate killed them and won the game. In the second case, I was going up the hill to harass a "red" (because my team mate and a red were trying to "get" each other and both were on low HP). Well, half way up, my team mate dies, so I stop on the path and pre-aim at the path coming down as I figured they would come down that way (they knew I was there ... intuition). Anyway, some artys cannot aim straight ahead, so I backed up onto a rock to push my nose down, and waited. About 10 seconds later, the heavy comes down and I "shot gun" him and win the game.
Another tactic is watching your flanks and seeing which flanks are failing. Earlier today, I saw that the west flank "good guys" had all died, so I figured the enemy would come that way. I was able to move east and pre-position my shots to that location. Sure enough, my arty teammate (who would not follow me) dies as he lights up an enemy ... and I took him out.
Finally, watch the map carefully ... you can, but the other tanks cannot ... they are too occupied trying to not die and kill the "reds". When I see a flank die, I call it out and hit my HELP key (F7) ... sometimes it get's others attention and they re-position ... but I stress "sometimes", like 10% of the time. Usually your ignored but it's worth a try.
And remember what Vince Lombardi once said ... "it's not like it's life or death ... it's much more serious than that".
