Load a little more than last time
The whole of strength training in one sentence, and most people skip it.
Do this
Record what you lift or how far you run. Each cycle add a small increment - weight, reps, distance or reduced rest. Keep the increments boringly small. When progress stalls for several sessions, reduce the load and build back.
Why it works
Adaptation responds to a stimulus beyond current capacity. Without progression, the same session becomes maintenance. Progressive overload is one of the least contested principles in exercise science, and works for beginners across essentially any reasonable programme.
Where it fails
Progression cannot be linear indefinitely - beginners advance fast, then it slows sharply, and pushing through that produces injury rather than gains. Sleep, food and recovery cap the rate. Programme details matter far less than most people believe.
How you’ll know
Look at your log from twelve weeks ago. If the numbers are the same, you have been exercising rather than training.