Here are a few tips for beginners:
- Don't be afraid of using a flash. Instead, get comfortable with using a flash on/off camera and learn how to shape light within a given scene. Remember when incorporating a flash you need to keep in mind that you are making adjustments for 2 separate exposures within the same shot. The first for the ambient light and the second for the amount of light you want to output from your flash(es).
- After you've become comfortable using a flash, explore the basic types of lighting for portraiture. Paramount, loop, split, rembrandt, and profile. This will provide enough knowledge and experience to help you customize your own setup to illustrate your vision.
- Every lens has a sweet spot. Gain an understanding of the specific limitations and advantages of every lens you use. This will help you understand what type of lens you should use given environmental conditions, distance to subject, desired depth of field, and creative vision.
Don't underestimate lighting. Position and type of lighting, continuous, spot or flash lighting make all the difference. Don't rely on your cameras ability to work under low light, a camera body is only 1/3rd of the technological aspect of taking the picture or video. The other 2/3rds are lens and lighting, people remember the lens, but forget lighting. Even if you get all 3 parts, it depends on how artistic you get with them.
Invest in lights, instead of bodies and you will see the difference. Learn 3 point lighting (master, key and back lighting).
After you learn about lighting. Play around with lighting too... learn what works and what doesn't... you might like shadows in certain parts of your subject and/or other parts of the frame.