Most people do not have an orchard or a garden filled with ripe fruit to be picked. Most of us buy it at the grocery store up, and it was picked and shipped usually before it was ripe. As a piece of fruit gets ripe, it goes from a hard, sour, and inedible object in to something with a bright color, soft and sweet piece of fruit.
Some other fruits, such as tomatoes, will produce the red or orange compound simultaneously as the chlorophyll degrades. Berries that are a blue red color will start to receive a deeper red as they start to get ripe. Most of these fruits - bananas, apples, tomatoes, and cherries - do show they are getting ripe by the color shift.
Another way you can tell that some fruit is ripe is by the smell. A lovely example is lots of types of melon. Changes in the chemical makeup of the fruit will cause them to make strong, pleasant odors. You can best pick a lovely melon by smelling the finish of the fruit where the blossom was, and pick fruit that has an aroma that is fruity.
Last, if your piece of fruit is a bit heavier than the others, this is a lovely sign. It usually will mean that the fruit is mature, and that is a lovely indication that the fruit is ripe. If your tomato or grapefruit is ripe, that is usually a powerful sign that it is ripe and prepared to be eaten. This can work well on melon, grapefruit and even sometimes oranges.