hi
which type of opamp do u need. There are variety of architectures of opamp. can u be more specific.The attached pdf contains the basic steps of designing an opamp.
If you want to study the op amp, I think you can fisrtly do some simply work about op amp.In my opinion,The Allen's book "cmos analog circuits design" is a choice for learning op amp.Beacuse it have many examples and teach how to simulate the op amp.