Working on high key

I got a new light yesterday so total =3 now. Yay. I really wanted to do high key the right way and it was just too difficult with only 2 lights. This was just practise this morning for my shoot later today. I had the camera set to an iso of 200 - for you non-photo types, iso is a way of controlling the light. Usually I have it set at 100 but with all the bright white I felt I should bump it up a little so so my f-stop wouldn't be so high. Even with an iso of 200 my f stop was 18 - yikes! I am not happy with the iso being so high. When I enlarge the image, I can totally see the grain. So, back to the studio so I can get it right.