For most modern fill valve adjustments, you typically won't need specialized tools beyond your hands. Some older or specific fill valve types might require a flathead or Phillips screwdriver to loosen a lock screw or a pair of pliers to gently turn a locking nut. Always have a towel handy for any minor spills.

While not strictly necessary for simply adjusting the float, it's a recommended safety measure, especially for beginners. Turning off the water at the shut-off valve behind the toilet prevents accidental overflows if you inadvertently displace a component. Remember to turn the water back on fully after testing your adjustment.

The ideal water level is typically about 1 inch below the top of the overflow tube in the tank. After each adjustment, flush the toilet and observe the water refilling. The fill valve should shut off completely once the water reaches this level, and the toilet should remain silent without any trickling sound.

If adjusting the float doesn't resolve the constant running, the problem likely lies elsewhere in the fill valve assembly or with the flapper valve at the bottom of the tank. The flapper might not be sealing properly, or the fill valve itself could be faulty and require replacement. Consider checking the flapper for wear or obstruction next.