If you want a quick access to it, read Razavi's book.
If you want to learn more details, read Allen and Gray's books. And try to find more materials in IEEE.
I'd like to recommend Allen's book, and the reason is you can find how to test(in simulation) the opamp's open-loop gain, ICMR, output swing and other parameters.
Step by step, just begin with some basic simple amplifiers.first read the book,and then you can do simulation with Hspice.
There are many books about op amp design, you can download it free.