For those of you who do not know what it is, it is basically carefully observing your opponent's trigger pulls. In Cardfight!! Vanguard trigger pulls are the main source of gaining advantage and the best way to turn the tides.
By watching what your opponent draws and keeping track of what cards (or at least the guard value they draw you can keep ahead of their game (in combination with magic numbers!)
This is best for some more competitive games but it's basically called "Counting Guard"
--Get to know card pictures and grades (Usually, grade 0s will have 10000 guard) Grade 1s and 2s will have 5000 and 3s have nothing
--If you can keep up with what they are checking then you can store a number of how much guard they have (and set a goal to waste a specific value before pushing fully for game)
--Ask your opponent if you can see their drive checks again, if they let you then make a quick note of the values and grades if you can (if you combine this with magic numbers their hand of 6 grade 1s and 0s can easily be brought down to 2 or 0 in a turn)
-- Keep moving on a strategic aggressive. When they have rear guards in the front row and they are grade 1s and 0s dont attack them, when they do have grade 2s focus at least 1 attack to try and bring down their interceptors, I'm pretty sure they will guard those. Make your opponent sit behind their unable to intercept Grade 1s because they will be forced to retire them before pushing, as opposed to you wasting attacks to clear them out for them.
Also less rear guards means less hand because they need to play more to cover themselves and be agggressive
The other most helpful thing to note about counting guard is considering triggers. If your opponent draws a card off of a draw trigger, or for their turn. You need to have a cushion zone for the "What-ifs" when they trigger draw you can always assume its 5000 added to their hand. In my opinion +5000 may be off but they will still need to be forced to use it at some point.
If you go on the offensive push and they top a trigger and boost their vanguard, its best to not fully commit to attacking their vanguard, and more onto their rear guards unless you can brush off that +5000 or have game. Alot of times my opponent or myself would top 2 triggers in a turn and the extra 10000 just makes trying to go for game less appealing. Especially after Counterblasting, it means they guard less and you waste more for an attack that almost instantly fails.
Its better to concentrate on your deck builds. The main motive should be to pressurize your opponent.