You need the right steel. Something shallow hardening like 1095 or W2. You need a way to differentially harden (clay or using heat control meshed with blade geometry) so that the edge hardens while the spine forms pearlite. You need practice to get what you want, and even then it can be a crap shoot. You need effective hand-sanding skills to really bring out the activity of the hamon. You'll want to sand 1000-2000 grit before etching for the finest presentation. You need a proper etchant (dilute Ferric Chloride, lemon juice, vinegar, etc). Then you'll want to repeat polishing/etching process until you are satisfied.
There are numerous threads on the topic with very detailed explanations of how it can be done. Search a bit and then ask questions if you're not finding what you want.
--nathan
