How to Fix Slow Flush Toilet

[ToomuchStuff]

Are you talking the float? If so, I know Fluidmaster style valves, have a replaceable rubber gasket/bladder, that can get gunk buildup, or eat up by chemical's thrown in the tank (like bleach tablets). The bulb style, I know you used to be able to get replacement bulbs and the gasket that goes to the tank for it (the gasket where it goes through the tank to the supply line, should be available for all styles).
I am not sure about the small, fill pro style valves (normally used in small toilets).
Also the flappers are replaceable, if the water is leaking into the bowl from the tank.
Shutoff valves, are either a ball valve (replace, not fixable, but lasts longer and quicker shutoff), or the traditional style (with a rubber gasket).

[Cypress]

I mean the water valve outside the toilet on the floor. The water pipe that feeds water into the tank. That shut off valve has a minor leak. I tried to tighten the nut but there's a small leak if the valve is too far in the open position. It's set almost to closed to stop the minor leak. I put a cup under the leak but this may require a plumber. The pipe has some green corrosion on it.

[SteveinMN]

The water pipe that feeds water into the tank. That shut off valve has a minor leak. I tried to tighten the nut but there's a small leak if the valve is too far in the open position.

Here you go. I haven't used these instructions personally, but they look right. It's at least a starting point for figuring out the parts you need to look at. Note the author's conclusion at the bottom of the instructions...

[Cypress]

Thanks Steve, I am considering calling a plumber for this task. I find that the area to work in is very cramped and I am not that strong. If I broke or bent something wrong, it would cost more. I can shut the water on and off when I need to flush. I live alone and it's only an inconvenience for me. In the meantime, I'll try and save up for the cost.