Keep flames under the base of pans. If the flames lick round the sides of the pans you are wasting gas. Only heat the amount of liquid you need. Do not overfill pans. Cover pans with a lid whenever possible. The food will heat up more quickly and there will be less steam in the kitchen. Try cooking more than one vegetable in the same pan, for example potatoes and carrots. Cut vegetables into smaller pieces. This way they will cook more quickly. A pressure cooker will save time and energy.