1) Why is focus fire needed?
Because if 15 vs 15 devolves into 15 1v1s, the more skilled 15 are at a huge advantage. Therefore, if the less skilled team can focus fire more effectively, they can claim the advantage.
2) Why does focus fire work?
For the math of it, Google Lanchester's Square Law, but the following video simplifies the concept.
3) Target Priority
You want to get guns off the field. 140 vs maus = 140. You can kill it faster and get the higher DPM gun off the field.
4) Call your kill shots
There is little worse than having multiple tanks shoot a dead one. If you are almost reloaded and 90% sure you can pen the one-shot tank, call it out so others can fire in the next target in priority.
5) Mods
I cannot stress how much mods can help. For example, this mod (which can be found in modpacks like Aslain's makes a huge bouncing arrow in the the T'ed target so it is hard to miss. Mod: _HawgJaws_'s 20 Target Markers Pack If you run no other mods, I suggest running this one. Let me know if you need help installing it. I run the yellow arrow in the first type.
P.S. If you are worried about whether or not a certain mod is legal, go to WGmods.net. This is an official Wargaming website and all mods on it are legal.
P.S. If you are worried about whether or not a certain mod is legal, go to WGmods.net. This is an official Wargaming website and all mods on it are legal.
6) Training room 1
Grab a mixture of TD, Med, Heavies. Pick some tanks that are hard to pen like 268v4, 279e, etc. Divide into 2 groups as equal as possible. Line up around 100m apart. Have caller "T" up targets. Use Target Priority. Do it silently. Once the caller Ts a target, others should T it as well. Calling out tanks, health and such are helpful to focus fire, but frequently there are 2 or more groups engaged at once. So by T'ing targets, you can focus fire without jamming up coms.
Strat Sketch: Click Here
Strat Sketch: Click Here
7) Training room 2
Same idea, but now both sides should defend themselves. Angle, Wiggle, use dead tanks or more armored tanks for cover, etc. No flanking, no hiding in bushes. The idea is to make focus fire harder, not ridiculous.