What cycling actually does
Fish waste and uneaten food release ammonia, which is toxic at even low concentrations. One group of nitrifying bacteria converts ammonia to nitrite—also toxic—and a second group converts nitrite to nitrate, which is only harmful at high levels and is removed by water changes and plants. "Cycling" is simply growing enough of both bacteria colonies in your filter media to process waste as fast as it appears.
The realistic fishless timeline
Week 1–2: you add an ammonia source (pure ammonia to 2 ppm, or a pinch of fish food daily) and ammonia readings climb. Week 2–4: ammonia starts falling as nitrite spikes—the nitrite phase usually lasts longest and is where people lose patience. Week 4–8: nitrite crashes, nitrate climbs. The tank is cycled when it converts a 2 ppm ammonia dose to zero ammonia and zero nitrite within 24 hours. Test with a liquid kit; strips are too imprecise for this job.
What genuinely speeds it up
Seeding with mature media is the biggest shortcut: a handful of gravel, a used sponge or filter floss from an established healthy tank can cut weeks off the process. Quality bottled bacteria products help inconsistently—treat them as a boost, not a guarantee. Warmth (26–28°C), good oxygenation and a pH above 6.5 all favour bacterial growth. What does not help: changing water during a fishless cycle unless ammonia exceeds ~4 ppm, or swapping filter media mid-cycle.
Fish-in cycling, if you are already committed
If fish are already in an uncycled tank, it is manageable but demands discipline: feed lightly, test daily, and do an immediate partial water change whenever ammonia or nitrite rises above 0.25 ppm—which can mean changes every day or two for several weeks. A dechlorinator that temporarily binds ammonia buys safety between changes. Stock nothing new until the tank fully cycles, and expect the process to take at least as long as a fishless cycle.