Most people hit RRTCM pretty early off, if not their first book, thus they should go through it step by step. If you are one of those rare birds that is starting off with Erdnase, then go through chapter by chapter, move by move, attaining at least a rudimentary understanding of a move before going on to the next technique. Most of us don't get into Erdnase until we are intermediate so at that point I think you can browse through it and cherry pick what you want. I would however recommend reading the beginning chapters carefully to get an idea where the author(s) is(are) coming from. If you are more interested in techniques for general card magic you might skip ahead to Legerdermain and if your reason for studying it is to improve on gambling demos then study the artifice chapter carefully. Have fun!
