What type of scrying do you want to do? As there are a few ways to scry, through a mirror, crystal ball, or in a bowl.

How I have learned to scry is that it is very similar to doing a tarot reading, you think of the question that you want to ask and then concentrate on looking in the mirror/crystal/bowl of water, and you should see some images or visions.

If it doesnt happen the first time, then dont worry, it can take a lot of practise.

Some people feel it is best that you meditate on the question at first and then look into the object.

There isnt really a right or wrong answer to what you could scry for, it is basically up to you on what you want to know.