First you need to buy green clothes, here is the list of them:

1.Dirty Long sleeved T-shirt $0.03

2.Pilot pants (beige) $0.16
or
Cargo pants (beige) $0.03

3.Long leather boots (brown) $0.06

4.Combat gloves (khaki) $0.25

5.Beanie (brown) $0.04

6.Utility belt (brown) $0.40

7.Cloth mask (checkered) $15.32

8.Rugged (beige) - M16A4 $0.03

When you have items bought, join the game look for M16A4, flash hider, darker lvl 2 helmet and lvl 3 or lvl 1 vest

NEVER PICK UP:
1.Helmet lvl 1 or lvl 3
2.ANY BACKPACK. I'm serious no backpack, it sticks too much from the grass
3.Police vest lvl 2
4.Second weapon
5.Melee weapons, just why would you?

Tips:
1.Try to find a spot in the shadow with long grass and a bush
2.Stick to the middle of the circle
3.If you have flash hider equipped shot enemies when youre 70% sure you will kill them before they hide behind rock etc. If you don't have flash hider then shot them only when your 100% sure
4.Try to not move or make any noise while you're hidden. If you need to check where is enemy use "alt" key, your character wont make any movement
5.I recommend playing FPP

Thanks for reading, let us know what you think about this strategy
If you have any questions feel free to ask them in the comment section