How do I fix the toilet that is letting too much water into the toilet and not flushing it all out?
I have tightened the handle, moved the chain back and forth. Some times it drains all the way, most times not.:confused:

Adjust the float in the tank at the rear of the toilet,hence less water in tank less wate in toilet , also check to be sure there is nothing that the flapper valve can get caught on during the flush.

I agree with 'canbeefixed' on most parts, putting a few bricks under the float can help it to pu out less water. This way, u protect the environment by saving water and you yourself get what you need.