As I learnt from my parents and later from books. The amount of water should be in proportion with volume of rice. For example, one cup water should go with one cup rice before putting it over the flaming stove.
Note: Some need less while others need more. A bit adjustment maybe necessary with every rice batch purchased.
Specifically, this is how my parents thought me how to cook rice. Get rice using the improvised measuring container. Usually an empty medium can of evaporated milk or other thin can of comparable size.
Wash several times with generous water until the last washing is clear and no visible floating dirt.
Then here is how to add the right water volume.
Discard the last washing. Make the washed rice as flat as possible. Measure the depth with straightened palm. Finally, add water equivalent to that depth.
This method is fine for expert cook but too crude for newbie. It is a hit or miss technique that often misses. Before, mine would end up too wet, too dry, raw and rarely nicely done. I often chose the frying jobs to avoid mother’s anger.
The rice flatness when adding water is disturbed. The water measurement will be wrong when the palm is placed in shallow or deeper area.
The cauldron wall is not straight from bottom to rim. Obviously, equal thickness of rice and water above does not mean they are of equal volume.
Here are some tips that I like to share.
If you feel the rice at hand is clean enough. Measuring equal volume rice and water will do the trick.
If washing is necessary. Do the method mentioned above. Stir well. Drain water to separate container. Measure it. Get equivalent amount to be added back. Repeat until satisfied. This way, we have avoided the measurement guess work. We have measured the right volumes and just replacing the loss water with every washing.
Use electric rice cooker whenever possible. I have never missed once with it. It is fast and energy saving. Contrary to what you have in mind. Yes, it gonna raise electric bill a bit but will save on gas and firewood. In addition, as soon as cooking is started, you can leave it and do other important tasks. Even watching TV and falling asleep is allowable.
If using firewood or LPG. Bear in mind that it should go into running boil as quickly as possible. Set the flame to high at the beginning and lowering gradually toward the end. Easier to do with lpg stove and a lot harder with wood fire. it is kind of erratic. Flame is hard to start. It will become to strong and suddenly to weak and extinguished.