The short answer
Make a workout harder when you can complete your current work with stable technique and it no longer feels especially challenging. Change one thing at a time: add a repetition, use a slightly heavier weight, improve control or add a set. Keep the increase small enough that you can still perform the movement well.
Progress is a gradual adjustment
Progressive overload means gradually asking your muscles to do a little more over time. “More” can mean one extra repetition, a slightly heavier weight, an additional set, a longer range of motion or better control. You do not have to add weight every week, and a workout does not need to become harder every time you do it.
First make the current version repeatable: use a comfortable range, consistent technique and a load you can manage. If the final repetitions are still controlled and the work has become noticeably easier across more than one session, that is a sensible moment to adjust one variable.
Change one thing, then observe
Small steps make it easier to tell what helped and to avoid a jump that turns a familiar exercise into a struggle. For example, if you have been doing 8 repetitions with a dumbbell and could comfortably do several more, try 9 or 10 next time. When the top of your planned range feels steady, move to the next weight and return to fewer repetitions.
Keep the change modest enough that you can still control the movement. If you feel sharp pain or your technique changes substantially, stop, reduce the challenge or choose another variation. Progress also includes returning consistently after interruptions; it is not a straight line.
A practical example
If you have been doing 8 controlled rows with a dumbbell and could comfortably do more, try 9 or 10 next time. Once that range feels manageable, consider moving up to the next dumbbell and returning to fewer repetitions.
Try this next
Pick one exercise and write down the load, repetitions and effort from your next session.
Want more structure?
This article is a useful starting point. The Strength Edit offers a more complete framework to keep building on it.
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