Hydrokinesis is the psi power to control and manipulate the movement of liquid water using the power of the mind. In beginning levels you would make ripples in water, almost unnoticeable at first. This skill takes much trial and error before seeing any results so don't give up too easily if you did not get any achievements yet. In advance levels you should be able to cause the water to jump around in a bowl or glass water, to causing movements in small rivers and lakes, possibly oceans if the skill is improved. Combined with Cryokinesis, this would make an excellent ability in making ice, and freezing water. Like all abilities, it's Psychokinesis with water, but it doesn't have to be that way.
Once you think your ready for hydrokinesis take a medium - large bowl and fill it with Water. If the bowl is glass this may be easier because you can see all of the Water within. Now place a cork or something similar which floats in the bowl and wait for it to settle. Once it has settled, close your eyes. Sense the water in front of you, feel its energy and merge it with yours. See in your mind's eye the link between you and the liquid. Feel its smoothness, its cool healing properties.
Now try to mimic those feelings within your own energies. You and water are one and the same.Just as you have control over your own energies, so too do you have control over water. Then Open your eyes. Look at the substence within the bowl. You are a part of it, and it is a part of you. Keeping in mind your connection with it, will(command) the water to move, just as you would with your own energy. Make it start to swirl in the bowl, always getting stronger, always gaining speed. It is you. Continue to do this until you feel you have succeded or are in need of rest. Don't over do it on the first few tries. Have a mental rest after, you need it!
If you have a pool or a sink get something light that floats and try to move by imagining water currents moving towards the object pushing it like a riptide growing stronger by the second and after a couple of training sessions it will start to move dont get discouraged if it takes long to learn this training.
This is also a good beginners training you can learn hydro by pouring water into a glass and absorbing the energy of the element. Then you can imagine the water pulling itself apart rapidly and coming back together.
A easier way to absorb energy from the element water is to imagine that water is flowing throughout your whole body like your blood and that your hands and body are water with a hard smooth surface and rough interior flowing throughout the body constantly as if it is what keeps you alive and that every breath of air is adding water to flow throughout your body replenishing the good water and clearing the bad water or blockages that stop the flow. Do this for 15 minutes or more everyday and you will master this skill and it will seem like water is flowing throughout your body constantly without having to even think of it.