I taste wine every time I rack or otherwise touch it, post-fermentation.
Craig's response made me think more about what I'm perceiving when I taste. I mentally block the CO2 aroma/taste, and get an idea of the overall aroma, fruitiness, how strong the wine tastes (depending on the source fruit), how tannic it is, how acidic. At pressing/first racking I can get a fairly good idea how good the wine will turn out. This is far from exact, more of a hint in the direction the wine will progress. [I'm going to start tasting the must.]
When tasting I usually take 2 sips -- first one I swirl in my mouth and swallow to cover other flavors. The second one I swirl around and hold, letting it contact the inside of my mouth in all places. Then slowly swallow.
It helps me pick out different things -- in a recent post I commented on the differences in tannin between the barrel aging and unoaked topup wine for my 2022 Tempranillo. In one the tannin is most noticeable on the gums, and the other along the sides of the tongue, probably a difference between grape and oak tannin.
A lot of this requires experience -- taste every wine every time you rack or otherwise touch it.
Note that this affects your volume. Each month I draw a 4 oz sample from each barrel, and over the course of a year this adds up to 1.5 liters of wine, e.g., 2 bottles. If you don't have overage, it doesn't work as well, although if you have a compatible wine to top with, that's ok.
As Bernard pointed out, tasting along the way teaches us the progression. That's the reason I suggest opening a bottle every month or two, to continue that education.
This is nothing that can be taught remotely, or from a textbook. We can and should talk about it, but tasting the wine is a requirement for learning.
Yeah, like this is a tough thing to do, right?