A few changes this page needs:
Bad colors on avoiding engaging multiple targets
Given the advice is to stay hidden from two tanks and only exposing to one, the desirable zone should be in green, and the undesirable zone (visible to two tanks) in red. Only if the advice was to the two tanks attacking would it make sense to show the graphics as they are now.
Tree and soft cover advice
It's bad advice to never knock down trees ever. There are lots of circumstances where it's necessary or useful:
1. On sparse maps or where tall trees not bushes are in the most desirable sniping spots, especially on some of the assault maps, there is no way to get good cover without knocking down a tree. Tanks are almost always going to be in some of those locations, so knocking down the necessary trees in the necessary direction right away early in the game makes it impossible for arty to detect who is in which cover when - if a light knocks the trees down and then runs off long before the slow tanks arrive to occupy the cover, the arty may waste valuable time shooting at nothing also.
2. The general tactic of lights covering for snipers and arty by knocking down trees where they aren't right now, to distract from where they really are, is generally useful in the early game, especially if the light is actually trying to find out where the arty fires from, so they can go kill it and end the threat to the snipers entirely.
3. Knocking down trees makes them more useful as cover, basically turning them into a hedge. But knocking down soft cover like buildings generally makes them far less useful. Thus smashing up soft cover where it's useless to your side, but valuable to the other side, is a valid tactic especially early in the game when there is little or no fire onto those locations - like your own base. I can't think of any reason to leave soft cover in place on your own base in the standard game, why not smash it all up so resets can be done from a distance from any angle?
4. Some maps are so forested you are going to knock down trees, period, unless you dodge them with great care, which slows you down and gets you killed. Knocking down a lot of trees along a well known early game route isn't going to tell the arty a damn thing they don't know, and they can't really zero in on a particular tree out of a line of trees and nail you, if you're weaving even slightly as you go. You also create great cover for the snipers that follow to hide in, and as slower tanks they are far more vulnerable to arty when they knock a tree down, so it's best for the light to do it for them, attract any fire immediately, so it becomes obvious to the snipers that arty is watching that line of trees. Then they can pick unusual positions behind the tree cover to minimize the chance of being shot, and of course if there are no more trees to knock down, arty gets no more information about them for the rest of the game by watching trees.
5. Some games have no arty. In these, at least, tree and soft cover cues are far less important.