First - You need access to a quality grinder and espresso machine. If you do not already have one in your house, I would recommend getting a setup. It serves two purposes: 1) to feed your addiction and 2) to practice. I have the Rancilio Silvia and Rocky (doserless) grinder. I love it and it pours as good of a shot as the commercial Rancilio we have at work. My next step up is going to be a dual-boiler home espresso machine (no need to "charge up" the steam wand. But with the commercial setup at work, I have no immediate need. A decent home setup will set you back about $800 - $1800 (single boiler / double boiler).
Second - I would purchase David Schomer's "Techniques of the Barista" video. It's a little pricey ($80), but well worth it. It covers all aspects of extracting the perfect shot (grind, tamp, temperature, golden rule, etc.). It also covers steaming milk for the various drinks (a science). Once you open up your shop, the video will also serve as a training video for your staff (if you don't have a deal with your bean vendor to provide training).
Those are my thoughts, but those two points above have served me well. The only other thing I would do is continue to read forums, web sites, articles, etc. on the extraction and milk steaming techniques.
...and practice, practice, practice!