Other than flowering very early and LST/tying down etc... then it's all about genetics. Lowryder is one, I think, that remains compact.
Indica dominate strains will grow shorter usually. Also if you want short plants just veg them until they are like 6 inches tall then flower them. Some auto flowering or self flowering strains will sometimes glow shorter because they will flower after a specific amount of time no matter the hight. You can also top your plants to keep them from getting too tall.
Well, you can't so much keep them dwarfed as force them to finish small, but that's certainly possible. If you start the plant right off at a 12/12 cycle, you will get a very tiny finished plant. How small depends on the genetics, but you can do this to some degree with any of them.
to keep small plant in small red cups used for like drinking. what it does is eliminates the space for the roots to grow. this keeps plant small and will finished budded after lights are changed to 12/12 after vegitation