Your taste buds are the best guide. If your coffee tastes flat or weak, you might be under-extracting. Try a finer grind or a slightly hotter water. If it's harsh and bitter, you're over-extracting. Go coarser or cooler.

Another common issue is uneven extraction, often from pouring too aggressively. Keep your pours gentle and steady. And don't forget to swirl the brewer gently after your last pour to flatten the bed—it helps everything extract evenly.

Remember, coffee is subjective. There's no single 'right' cup. Trust your palate and adjust one variable at a time so you know what's making the difference.