tactic 1 is pretty simple, just angle your armor to the enemy that your attacking. KEEP IN MIND: always angle your armor BEFORE attacking the enemy tank, so when he sees you he has no chance getting a good shot at your weak front (by the way this tactic won't work if you are driving the sherman with the rounded armor. It's like angling your armor in an IS 3: you make it even worse.).

when you're driving the Sherman with the rounded armor, you should try not getting in direct sight of the enemy because when you angle rounded amor it won't effect the chance of a ricochet - even the opposite! You are basically showing them flat armor, so to avoid getting one shot you should think like a KV 2 or like a light tank.

KV 2 tactic: stay in one position; peek out, shoot, hide, reload, peek out, shoot, and so on...
it's pretty simple.

light tank tactic: After the round had started, go straight right ( or left) and try flanking the enemy, when you, for instance, flank a reloading KV 2, he's pretty much screwed! As I said: STAY OUT OF THE DIRECT ENEMY SIGHT, or they can easily kill you with one or two shoots.

there's not much to explain here, just try staying with 2-3 teammates so you are not alone and vulnerable. but don't be that guy who runs in the sight of the teammates and blocks their vision, IT WON'T HELP YOU OR THEM so try staying behind them and not infront of them.

in a sherman you don't have much armor even an ice-cream truck can hold more hits than you!

so here are some of the tanks you should avoid getting in direct sight of:

I HOPE THIS HELPED INCREASING YOUR CHANCE OF SURVIVAL IN THE FIELDS

GOOD LUCK