Molecular kinetic theory tells us that the molecules of a substance are in constant motion. This motion will depend on different factors such as volume, pressure and temperature.
For the gaseous state, pressure greatly affects the motion of the molecules. On the contrary, for liquids the pressure affects little because the molecules are closer together and for solids its interference is almost nil. We would need a very high amount of pressure to have a significant effect on solubility in this example.
In contrast, temperature will greatly affect the movement of the sugar and water particles. By increasing the temperature we will be giving more energy to the molecules and the motion will increase. Therefore the solubility and diffusion of the sugar in the water will be faster and greater.
Therefore, to increase the rate of dissolving what we can do is to increase the temperature of the mixture.