Use of Hands
Use of hands is the most common method used in kitchen by women folks to measure different cooking ingredients without availability of a measuring cup. The routine practice makes them even more perfect than a measuring cup. However, the use of cup or teaspoons in first few days is necessary for development your skills of perfect judgement. It is because that frequent use of cup leaves no need of the cup at the end, because more or less the measured quantity is the same every day and that develops common sense. Measuring tea, sugar, rice, flour and salt is dead easy for one who works in kitchen almost daily.
Use of Cloth
If you do not trust your judgement of measuring things on your hands, you can use a piece of cloth. The process is to spread the cloth on the kitchen table, and pour a cup, a half cup and one-third cup, one table spoon and a half table spoon of any ingredient or all ingredients one by one. See size of each quantity carefully and try to keep in mind for the future use. If you are able to pick up the sizes of all those quantities you can use the same cloth way for measuring things without a measuring cup every day.
Use of Bowl
You can also use a bowl to measure quantity of ingredients in a bowl the way you did on the cloth. Measure each ingredient by a cup for the first time and then pour it into the bowl and then use the size of each ingredient in the bowl for future judgement.