Still learning how to use VB coding to it's most effectiveness...

I have two sheets. sheet1 and sheet2. I want to pull the value of
cell(2, "d") from sheet1 and compare it to every value of column "d"
in sheet2, highlighting as it goes by. Once it has finished I want it
to go to cell(3, "d") in sheet1 and do the same thing, comparing
itself to all the values of column "d" in sheet2. I know how to pull
the variable I want, I know how to do the highlighting code, and I
know how to do the loops and whatnot. What I do not know how to do is
referance seperate sheets. help??