I've found the hardest part of my job is actually hiring good people to work for me. Do your background checks and make sure you hire the right folks for your position(s). There's no reason to waste your time with poor workers, especially with the economy the way it is and jobs so scarce.
Once you find a great worker for an advanced position in your company and they're helping make you some real money, do whatever you can to keep them around. More responsibility, an increase in pay, adding a job perk, ect. You will pay twice as much to get a newly hired worker correctly trained and you will be making much less money while training them... and that's assuming you hired the right person for the job. If they don't work out, you're starting from scratch all over again.
Continued education for whatever field you are in is HUGE. Seminars, trade shows, reading books, community college classes, talking with people in your field or your vendors and asking great questions... the more you know, the better your company will be, the more money you can make. When you stop learning, your business will stop growing.
It's MUCH much cheaper to get a past customer to become a repeat customer than attract new customers.