So, I’ve been playing GZ since it launched in March 2019, but the furthest I’ve ever got north was when Alpine Unrest released and I snuck myself to Himfjäll.
The reason for this is that I always avoided fighting anything bigger than a hunter, so I have no practice when it comes to fighting tanks and harvesters, which makes them even more intimidating, which makes me avoid them even more, you get the picture.
So, do you have tips how I can deal with the big guys ?
Heck Hunters freaked me out when I first started playing when they started carrying the gauss cannon.
Throw flares/fireworks to distract and use buildings/terrain to your advantage. You can also throw down a smoke bomb and stand in it and fire at them.
Lot’s of options ahead of you. You can also join a MP game and join a few fights to see how other people do it.
I just run up fire and hide, fire and hide, distract, fire and big machine go boom.
Sneak upt to the tanks, EMP them, get close fast and shoot one gunt off. I usually shoot the MG first. Than go back out of the close range attack range and shoot the second weapon.
Have you played continuously since GZ’s release, and not yet taken out any Harvesters or Tanks? 
When fighting a Harvester, you want to take it out quickly. The more time you spend fighting him, the more Hunters he will call in for help. Get up to mid range and circle around it, while shooting all you got at it. It’s whole backside is basically a big weak spot.
With a Tank it’s smart to shoot off it’s weapons first. Either EMP him and do it up close, or snipe them off from cover. It’s good to have some open ground around you. If the cover is too thick you’ll be trapped in the Tank’s bombardment. The best thing is to have a small hilltop between you and him. Then you can peek up enough to shoot it’s body, and his weapons will be too low to shoot you. Just always have enough room to run when it fires it’s rockets at you. The PVG 90 is a must-have when hunting Tanks, makes it a lot easier at least.
Please tell, what weapons do you have available?
Based on the other replies there are several different ways to take down a tank
I would honestly say it also depends on what Class it is Prototype, Military, FNIX, Apocalypse
All Tank Classes comes equipped with two ranged weapons and one defense weapon these weapons can vary depending on class.
The first is a machine gun and the second may vary between grenade launcher and rocket launcher.
Apocalypse tanks are equipped with rolling mine launchers which in turn is very easy to avoid but also have a machine gun that can deal extra fire damage over time
Pictured below is a Military tank. these are the most dangerous in my opinion due to the splash damage the rockets can do.
In general I would recommend you destroy the Machine gun (Orange) This goes for all tanks
but for the Military class you can also destroy the Rocket launcher (Yellow) since it has an additional 3rd weapon which serves no function (Green)
Here is a FNIX Tank equipped with a Grenade Launcher insted of the Rockets Launcher that military tanks has. The Prototype class has the same ranged loadout as the FNIX class
Note that FNIX and Apocalypse tanks also comes with Tick dispensers
And Finally the Apocalypse
For this one I would highly recommend to take out the machine gun while almost ignoring the mine launcher do note that it’s ticks are more annoying and can cause more damage to you.
But I would highly advice you against fighting an Apocalypse tank until you are more confident with tanks.
All tanks also comes equipped with Defensive weapons also depending on class
Prototype and Military have a type of shock wave that can easily knock you off you feet and launch several meters away all while doing high damage.
FNIX Class comes with Poison gas which will deal moderate damage over time
And Apocalypse has a “Firewall” which cases high initial damage but also fire damage over time.
I would recommend a sniper rifle to take out it’s machine gun while staying in cover before you approach it closer.
So now when it’s disabled (more or less)
we need to destroy it.
I would recommend to aim for this parts in the main body of the tank since they are easy to hit
you can also go for this points but you have to break its front armor plate which shouldn’t be too difficult
The tank’s legs are a little better protected so it could take a little more work.
the knee joint is all about angle while the upper square component has some armor.
Finally some better indication on it’s components
