What you need:
Voice
Concentration
Water
Quiet place (music optional)

Sit down in a quiet place or with soft meditation music playing in the background. If it makes you feel more relaxed, go ahead and meditate for a few minutes.

Set the glass in front of you if you haven't already. Place your hand over the cup and say three times:
"Water water flow through me I truly believe"
then say ''by the powers of three so mote it be!''

Then concentrate on the water and try to move it. It should take 1-3 days for you to fully be able to do it without being in a quiet area with lots of practice.