Learn how to troubleshoot a toilet that won't flush at your home in simple steps. First lift the lid and check whether the float ball is broken or touching the sides. Bend it a little if its touching the sides or replace it if its leaking or broken. Now check condition of the flapper valve and replace it if needed. Now check the handle, if its loose tighten the screw inside to fix it. Finally check the chain and replace it if broken or correct it to the right tension to lift the valve.