Who hasn't been annoyed by the incessant sound of a running toilet at one point or another? It's not just the noise that can drive you bonkers. It's also the dent it makes on your water bill. So, instead of helplessly watching and listening as your money flows down the toilet, let's jump into the DIY spirit and tackle the problem.

First Things First: Gather the Following

Before breaking into any repair work, always ensure you have all the right tools at hand:

1. Adjustable wrench
2. Screwdriver
3. Plastic cup (for bailing water)
4. Rubber gloves
5. Towels for backup (because it's never too silly to be prepared!).

By now, you should be all set to play detective.

Step One: Solve the Mystery - Why is Your Toilet Running?

Like all good repair folks, first, we have to get our hands dirty and identify what's causing the problem. Here are the usual suspects to investigate:

Float Ball Trouble

Does your float ball look like it's thrown in the towel and done its last float? If it's not rising correctly, it may be causing the water to overflow into the overflow tube, and there's your culprit.

Flapper Valve Leakage

If the flapper valve — the little sucker at the bottom of the tank — isn't sealing correctly, it may be causing water to leak into the bowl. To test if it's the offender, try the food-dye method: drop a few drops of food dye into the tank and wait 15 minutes. If the water in the bowl changes color, you've got a case of a leaking flapper valve.

Faulty Fill Valve

A fill valve that's not shutting off correctly can cause your toilet to run continuously. To confirm if it's the guilty part, try turning off the water supply to your toilet. If the running stops, you have your answer.

Step Two: Fixing the Issue

Now that we've played detective, it’s time for action. Based on the problem found, here's how you can fix it:

If you have a Float Ball Problem

Float balls tend to get corroded over time. If you identified this as your issue, you'll need to replace it, and here's how:

1. Open the tank lid safely and get a look at that old float ball.
2. Unscrew the corroded float ball.
3. Attach a shiny new one.
4. Adjust the float arm so the fill valve shuts off correctly when the tank is full.

If you have a Flapper Valve Leakage

1. Turn off the water supply to your loo.
2. Flush to empty the tank.
3. Unclip the old flapper from the bottom of the tank and remove it.
4. Snap on a new flapper.
5. Adjust the chain on the new flapper. It should be just long enough for the flapper to seal properly.

If you have a Faulty Fill Valve

1. Shut off the water and flush to empty the tank.
2. Remove the old fill valve by unscrewing it from the bottom of the tank.
3. Install a new fill valve securely.
4. Connect it to the water supply line.

Let's Wrap This Up:

Once the new parts are installed and your tank is reassembled, you are officially a toilet repair master. Forget about calling a plumber; from now on, you're empowered to save the day (and the water bill) should your loo decide to have a mind of its own again.

So, embrace the satisfaction of this victory, and remember — there's no home repair issue too overwhelming for a determined DIYer like you. Keep your tools nearby, your can-do attitude alive, and flush your worries away. Happy repairing!