The best advice is to learn everything. The best way to succeed is to be better then the competition. If you want to make the money you need to be diverse and offer design, installation, lighting, holiday lighting, applications, maintenance, and anything else you can think of. Every service you offer the goal should be to be the best at it you can possibly be. Your drive, business skills, organizational skills, and team building skills will ultimately determine how fast your business grows. There are guys who do millions in sales after just a few years and other guys who flamed out because they lacked all the skills required to properly grow a business. You do not want to grow a business too fast because you will not be able to manage quality control as well.