A leaky toilet can be a challenge to fix because they aren't always easy to take apart and work with. If you have to work on a toilet it is best if you have the parts you will need first so you don't have to leave the toilet all apart while you run for parts. Most hardware or home supply stores will allow you to return parts that you don't use so don't be afraid to over buy to get the job done.
If you have a leak coming from the tank and dripping on the floor of the bathroom, while the toilet is just sitting there and not being flushed, the leak is most likely coming from the bolts that hold the tank to the toilet. At worse, it could be a crack in the tank, but I have never experienced that. I have only found water coming from the bolts holding the tank on to the toilet. To repair the leak you have to shut off the water supply to the toilet and flush it until all of the water is gone from the tank. There may be some water left in the tank when it stops going down as you flush that will need to be sopped up with a sponge.
Once you have all of the water out of the tank you will have to remove the bolts holding the tank on to the toilet. When you have one of the bolts removed you will need to put a new washer on it along with some caulk. I have never had a new washer seal completely with out using some caulk. Put caulk on both sides of the washer and re-install the bolt and washer into the tank. Repeat the same steps on the other bolt. If you carefully remove one bolt at a time and replace the washer then put the bolt back before you remove the other bolt you may be able to get away without removing the water supply line. If you find that this is not the case you will have to remove the water supply line also.
After you replace both washers and caulk them you can re-install the water supply line and fill the tank and check for leaks. If you had to remove the tank you will have to flush a couple of times and watch for leaks from the gasket that connects the toilet tank to the toilet itself. The only time water passes through there is while the toilet is flushing. If you notice a leak coming from there you will have to re-seat the gasket between the bowl and tank.
