A superset is two exercises done back to back with little or no rest between them. Used well it takes twenty minutes off a session; used badly it just turns one tired set into two.
Pair exercises that don't compete
The classic pairing works opposing muscles: biceps curls after push-ups, rows after presses. While one muscle works, the other recovers, so neither set is worse than it would be alone.
Upper-lower pairs work too — lunges with dumbbell rows, for example — as does pairing a strength exercise with a stretch or light core work. What never works is two big lifts fighting over the same muscles.
If you are unsure where to start, the push-up and the dumbbell row are the safest first pair: one pushes, one pulls, and neither leaves you too shaky to do the other well.
Set up both stations before you start
Supersets die at the equipment swap. Choose both exercises and both weights first and place everything within a few steps, so the changeover takes seconds instead of minutes.
In a busy gym, carry a plan B: if someone claims your second station, the pair becomes two ordinary sets instead of a broken workout.
Count your rounds with a timer or out loud: the whole point is rhythm, and an untracked superset quietly turns into a normal set with extra walking.
Go straight from one to the other, then rest
Finish the first exercise and move straight into the second: that is one superset. Rest sixty to ninety seconds after the pair and repeat.
Three rounds of a pair replace six separate sets with about half the standing around. The work is identical; the dead time is not.
Respect technique when fatigued
Breathing hard changes how a set feels, so pick stable exercises for supersets: machines, dumbbells, push-ups, lunges. Save the heavy barbell lifts for normal sets, where a wobble costs less.
If the second exercise falls apart earlier than it would on its own, the pair is too demanding. Rest longer between rounds or lighten the second movement; sloppy reps are not extra training, they are practice at moving badly.
Use supersets for accessory work, not main lifts
Supersets shine on isolation and accessory moves: arms, shoulders, core, the exercises that usually live at the end of a session. Your heaviest squat or bench of the day deserves full rest and full attention.
Time the difference once and you will keep the habit: log the same session both ways and compare. Bulky records your sets with notes, so you can see which pairs saved twenty minutes without costing a single rep.