I have written here before about my inability to get satisfactory results when I cook rice by the absorption method. Boiling rice in plenty of water always produces separate and distinct grains; too often, when I cook the rice until its covering of water has disappeared, I end up with a cloggy mass. But I do not want to give up. By trial and error, I have arrived at methods that work pretty well.
The reason rice gets sticky is that it has overcooked. You need to learn the propensities of your brand. Most types of basmati, in my experience, take 10 minutes to tenderise, with a little steaming time on top; but they absorb different quantities of water.
I have had the best results with the Crazy Jack, Fair Trade brand. Put it into a measuring cup to assess its volume, transfer it to a sieve, and rinse it under running water. (Judging by the colour of the scum that rises to the surface when I boil rice, I reckon that it needs a wash.) Tip it into a saucepan, and pour over twice its volume of water. (Salt the water if you like; I am not sure whether salt has an effect on the consistency of the grains.) Bring the pan to a simmer, and turn down the heat. After five minutes, a good deal of the water should have disappeared. Cover the pan, and cook for five minutes longer. Turn off the heat, and allow the rice to steam for a further three minutes. Give it a stir with a fork.
Tilda basmati rice absorbs less water -- about one and a half times its volume. If you use more, the grains are likely to be sticky.