how long have you been trying? it can take months for some people, don't get discouraged.
try using lunar water, leave water in the moonlight [i go for 1 month, but you could leave it out for the full moon] the moon has always possessed deviation properties, lunar water might help you. meditate before skrying, clear your mind of all thoughts, and become totally relaxed. sometimes balancing your chakra's can help with srying. light a candle [white or purple] and place it near the water, but not so close that it's reflecting directly in the water. sit and stare into it, think of nothing [unless you have a question, then focus on that] look past your reflection and eventually you should see images.