I've always made cuts like K3 explained.
I discard the first jar, it is never any good.
Then collect until it begins to smell bad (tails), then stop distilling. Maybe wasteful but I can't tolerate tails.
Let it breathe a few days to drive off some of the off flavors and smells.
Starting with the middle jar I taste a bit of every jar, watered down to about 25 to 30%, and decide if it goes into the big jug or not.
If it does not make it to the big jug it gets recycled into the next batch.
Its OK to be a little brutal when deciding what are the keepers and what gets recycled.
Home distilled booze is so cheap there is no need to be greedy and ruin the jug with too much heads or tails.
As long as it tastes and smells good to you then you did it right.
If you take a sip and one eye closes and you make face like when you step in dog pile then you really need to work on your cuts
A pot still has to be the most difficult to judge the cuts. It is a long, slow smear from heads to hearts to tails.
Any kind of still that works on reflux, a packed column or bubble plate still, will concentrate the fractions and produce a more pronounced transition.
And they can give a few indicators. A reflux still that has sight glasses will show you that tails are about to start when the bottom glass begins to get foggy or when there is a sudden spike up in vapor temperature.
These are helpful indicators. Yet your best sensors are still your nose and tongue.
And for all of the above, you have to also consider the effects that aging has on the product.
If you plan to drink it young then it needs to be really clean - almost no heads or tails.
If you plan to age if for some years in wooden barrels then the booze will benefit greatly from a hefty dose of heads and tails, as that is where most of the flavor is. And why age booze for years unless it was for the flavor?