I guess my suggestions would be:
1. With respect to lighting, pick a line of strobes that you can grow with and add to, so accessories will work with all the lights. Buying quality units, instead of "economy" models, will usually save you money in the long term. Woodworkers can never have too many clamps, and studio photographers can never have too many lights.
2. Never under-estimate your local hardware store and fabric store as sources of studio accessories. Often, conventional items can be easily adapted to photo use at great savings over similar items sold for photogaphic use.
3. A top-quality multi-purpose meter (reflected spot, incident, flash & ambient), and learning how to use it well in the studio, is one of the best investments that can be made.
4. There are numerous books available that show typical portrait lighting arrangements. Each of the "good" ones will usually have a few pearls of wisdom that other authors may have forgotten. One of the best general lighting books I've seen is Hunter and Fuqua's "Light - Science and Magic" from Focal Press. Ultimately, lighting - whether for portraiture or commercial work - depends on understanding the nature of light, how different surfaces respond, and paying attention to highlights and shadows.