If you've come here wondering why every conditioner you've tried doesn't work for you, I urge you to read more about shampoo on my shampoo page as you may have product buildup. A good shampoo should make your conditioner work best.
You likely need a lot less conditioner than you'd think. To stretch out your conditioner be sure to condition on soaking wet hair to add slip and detangle with a brush to properly distribute your product. When water is added your conditioner may appear frothy, which is a okay. If it feels thick and buttery you may struggle, so try adding more water.
Rinse out conditioners will not work better if left on longer than the manufacturer says and leaving conditioner in your hair can cause more buildup and flaking.