4) You will need to have on hand water heater tape, small gas torch, solder, flux, plumbing sandpaper, pipe cutter, gas tape (to seal gas line) and maybe some pipe glue. Ask the sales person at the hardware store for a more defined list.
If you find that the water line repair leak is in the supply line you will need to replace it or simply tighten it. Start by turning the water supply off and then flushing the toilet to get rid of the excess water. Now use the towels to dry the area so that it is easier for you to fix the leak. Use a wrench to loosen the hexagonal nuts on the supply line at the main end as well as the one which goes to the flush tank. Now use the replacement supply line which you have and tighten the bolt at the supply end first. Now adjust the length that you will need for the pipe to reach the flush tank. Once you adjust the length use a knife to cut the extra length and then tighten the hexagonal bolt at the other end.
One other common design that is considered "washerless" was made famous by Delta and copied by several other makers. It uses little "cup" seals that fit over springs recessed in the back of the valve body. The springs press these "seals" against the cartridge and regulate the flow through little tapered openings in the cartridge. If you have one of these and it's dripping, changing these springs and seals will usually correct it. Here's a tip. Once you have the cartridge out of the way, insert a phillips screwdriver into the seal and pop both the seal and spring out. Stick the new ones on the end of the screwdriver to help guide them into place. This is especially helpful if you don't have long slender fingers.
Clean the hole in the gutter railing first. It must be free of any debris, so you may want to clean the entire drain channel using a proper cleaner. In this way, you will have a clean surface area which will allow you to repair the hole more easily.
Here are some general cautions. Do not begin jobs on holidays, weekends, or at times when plumbers raise their rates or are difficult to reach. Do start early leaving plenty of daylight to call a plumber if something goes wrong. Study the situation carefully. Think about what might happen if something suddenly broke and what the effects would be. Old corroded copper tubing might break in the wall when you are wrenching an angle stop that supplies the water line repair to your toilet. A flood in the wall could be costly. If the angle stop, on the other hand, is new and shuts off easily and you have another toilet in the house then it might make sense to repair the toilet yourself. Be honest, too. Are you handy with tools? Did you do well in shop classes in school?
Turn the water off at the main shutoff valve at the street. You should be able to take a pair of pliers(or your bare hands) and turn the valve at the water meter to shut off the water to your home. Once you have shut off the water you can cut the pipe around the leak and make the repair.
Over the counter drain cleaning products offer convenience and effective results. However, they are best left to those who need to simply improve the flow of water, not those who need to repair it.