think in terms of building blocks. each block has different functionalities. it's up to you on how to design the blocks with the desired functionalities. some functionalities like wave-shaping circuit, current mirror, etc, have their generic design. it's you who will customize it, on how much current it sources and sinks, what is the amplitude and shape produces by each blocks.
read books that concentrates on designing, not just theoretical explanation. sedra/smith's book is good. i also like m.h. rashid's book.